This document carries the Report that I made for presentation in college after completing 4 weeks internship at Siemens Rail Automation Pvt. Ltd., Bangalore. It hold the jist about what an engineering student from EEE, EE or ECE branch can witness and learn at SRAPL as part of their internship.

1. Annexure-I
INTERNSHIP
REPORT
On
ELECTRONIC INTERLOCKING FOR RAILWAY SIGNALLING SYSTEM
Submitted by
Aswin K P
11800868
B.Tech E.E.E. (L.E)
Under the Guidance of
Mr. Kishore Kumar T.N.
at
Siemens Rail Automation Private Limited (SRAPL), Bangalore
School of Electronics & Electrical Engineering Lovely Professional University, Phagwara
(June-July, 2019)

2. Annexure-II
DECLARATION
I hereby declare that I have completed by four weeks summer training at Siemens Rail
Automation Private Limited (SRAPL), Bangalore from 3rd
June, 2019 to 28th
June, 2019
under the guidance of Mr. Kishore Kumar T.N.
I have declare that I have worked with full dedication during these four weeks of training and
my learning outcomes fulfill the requirements of training for the award of degree of B.Tech in
Electrical and Electronics Engineering from Lovely Professional University, Phagwara.
Aswin K P
11800868
Date:

3. CONTENTS
Chapter 1: Introduction Page 01
Chapter 2: Abstract Page 02
Chapter 3: About Siemens Page 03
3.1: History Page 03
3.2: Siemens in India Page 04
Chapter 4: Siemens Rail Automation Page 06
4.1: Working with Indian Railway Page 07
Chapter 5: Scope of the study Page 08
Chapter 6: Railway signal Page 09
6.1: History of Railway signals in India Page 10
6.2: Types of Railway signals Page 12
Chapter 7: Work-plan with timeline Page 15
Chapter 8: Experimental work done Page 21
8.1: Designing and testing Page 21
8.2: Production and testing Page 26
8.2.1: Products Page 31
a) WESTRACE Mk-I Page 31
b) WESTRACE Mk-II Page 39
8.2.2: Installation address Page 54
Chapter 9: Conclusion Page 57
Chapter 10: References Page 58

4. [1]
1. Introduction
Internship is an integral part of engineering education and it helps us in getting direct
industrial as well as corporate exposure, which helps us diversifying our knowledge
about what are the various new developments taking place in the field of our interest,
which is impossible to achieve from just college education.
I opted Railway signalling as a field for my internship as I am fascinated by railway
industry. There are many multinational and Indian companies engaged in this field but
very few companies actually design and manufacture the entire components and rest of
the companies’ just install and service these systems.
The companies involved in designing and manufacturing the signalling and electronic
interlocking includes Siemens, Alstom, Kyosan, Hitachi, etc. So, I decided to go with
Siemens as they are the biggest supplier of electronic signalling and interlocking
equipments to all the divisions of Indian railway.
The division of Siemens India, which deals with railway signalling and electronic
interlocking is named Siemens Rail Automation Private Limited (SRAPL) and have a
facility at Bangalore, Karnataka.

5. [2]
2. Abstract
Rail Automation
Today more than ever speed, reliability and convenience are the desired factors for
ensuring the desirability of modern mass-transit railways – and therefore for their
commercial success. The key to meeting the criteria is optimum line utilization through
railway automation. Siemens mobility through SRAPL can commission the equipments
‘in service’. Train services continue to operate reliably, to the passengers’ satisfaction
and the systems remain highly cost effective.
Electronic Interlocking
In railway signalling, an interlocking is an arrangement of signal apparatus that
prevents conflicting movements through an arrangement of tracks such as junctions or
crossings. An interlocking is designed so that it is impossible to display a signal to
proceed unless the route to be used is proven safe. Electronic interlocking ensure that
railways operate safely. They monitor and control train movements on the lines
according to the operational requirements of the railway. Completely preassembled and
tested Interlockings, designed as modular containers play a key role in cutting time and
cost for installation and commissioning and so help reduce investment costs.
Need of Electronic Interlocking
The old manual mechanical and electro-mechanical signalling are being converted into
electronic signalling with electronic interlocking to make the overall system safer and
to eliminate the human error at all the possible levels. Electronic interlocking also helps
in making the entire signalling process automatic, which will reduce the requirement of
manpower and most importantly reduce the train delays and utilise the block section to
the maximum extend which will eventually help in increasing the number of trains and
increasing the average speed of trains.

6. [3]
3. About Siemens
Siemens AG is a German multinational conglomerate company headquartered
in Berlin and Munich and is the largest industrial manufacturing company in Europe
with presence and branch offices in the 6 continents.
The principal divisions of the company are Industry, Energy, Healthcare,
Mobility and Infrastructure & Cities, which represent the main activities of the
company. Company’s most profitable unit is the industrial automation
division. Siemens and its subsidiaries employ approximately 379,000 people worldwide
and reported global revenue of around €83 billion in 2018 according to its earnings
release.
3.1 History
Siemens & Halske was founded by Werner von Siemens and Johann Georg
Halske on 12 October 1847. Based on the telegraph, their invention used a needle to
point to the sequence of letters, instead of using Morse code. The company, then
called Telegraphen-Bauanstalt von Siemens & Halske, opened its first workshop on
12 October.
 In 1848, the company built the first long-distance telegraph line in Europe.
 In 1850, the founder's younger brother, Carl Wilhelm Siemens started to represent the
company in London. The London agency became a branch office in 1858.
 In 1855, a company branch headed by another brother, Carl Heinrich von Siemens,
opened in St Petersburg, Russia.
 In 1867, Siemens completed the monumental Indo - European telegraph line
stretching over 11,000 km from London to Calcutta.
 In 1867, Werner von Siemens described a dynamo without permanent magnets and
Siemens became the first company to build such devices.
 In 1881, a Siemens AC Alternator driven by a watermill was used to power the world's
first electric street lighting in the town of Godalming, United Kingdom.
 In 1887, it opened its first office in Japan.
 Siemens & Halske was incorporated in 1897, and then merged parts of its activities with
Schuckert & Co., Nuremberg in 1903 to become Siemens-Schuckert.
 In 1932, Reiniger, Gebbert & Schall, Phönix AG and Siemens-Reiniger-Veifa mbH
merged to form the Siemens-Reiniger-Werke AG.
 In 1966, the third of the so-called parent companies that merged in to form the present-
day Siemens AG.
Over the years since 1966, Siemens AG has acquired many famous companies and
indulged in joint ventures and expanded its reach and diversified itself and today has its
presence in almost all the fields that a person can think of.

7. [4]
3.2 Siemens in India
Siemens' long-term commitment in India began in 1867, when Werner von
Siemens personally supervised the setting up of the first telegraph line between London
and Calcutta. Today, Siemens has 22 factories located across the country, eight Centres
of Competence, 11 R&D centres and a nationwide sales and service network.
Fig 3.2.1: Major milestones of Siemens India
Foreign companies operating in India faced difficult times in 1977 when the Janata Party
came to power. The government wanted them to dilute their stake in their Indian units
and form joint ventures with Indian companies as part of an effort to boost indigenous
industry. The controversial policy led to the exit of US companies IBM and Coca-Cola.
But Siemens stayed back as it was working in the core sector. In fact, during the 1960s
and 1970s almost half the power plants and factories in the country were importing
technology and products from the German company. Though it had set up a few
factories, Siemens India used to import the majority of its products from Germany until
the 1990s. The India entry of European engineering companies ABB and Schneider
intensified competition. By the mid-1990s, Siemens India had doubled the number of
its divisions to eight as it shifted its strategy from importing products to local
manufacturing.

8. [5]
Despite facing huge losses, Siemens retained to work toward the development of the
country.
For over six decades, Siemens India has been the preferred technology solutions
provider, conceptualizing and implementing various flagship projects in Mobility,
Energy Management, Power and Gas, Smart Cities, Intelligent Infrastructure, Industrial
Applications, Healthcare and Smart Financing. Siemens India is also strengthening its
digitalization portfolio and working on select applications in the country.
Fig 3.2.2: Timeline of Siemens India (from 1867 to 2016)

9. [6]
4. Siemens Rail Automation
Rail Automation is a part of Siemens Mobility and comes under Automation.
For more than a decade, Siemens has been providing holistic solutions for the Indian
rail network to improve mobility, safety and reduce the carbon footprint. Siemens is the
leading supplier of complete rail automation products and solutions for all kinds of
railway systems be it Mainline or Metro.
SRAPL has registered office in Mumbai and a secondary facility in Bangalore.
Various products offered in this category include:
 Automation for Mainline and for Metro Projects (WESTRACE)
Siemens modern signalling systems are designed for safety, speed and economy. A high
standard of technical reliability and operational safety are ensured by incorporating
proven design and latest components technology. Siemens Signalling and Control
Equipment offer many advantages such as a Remote Control System in which all the
operations, dispositions and statistical data are centrally processed and automated. It can
handle the traffic with speed and safety. It is available for any range and size of
operational requirements.
 Relays
Siemens K50 Relay is failsafe, non-fault prone and a positive function. It is a vital
component used in Railway Signalling circuits. Its series contact layout serves optimally
in case of contact rupturing or breaking reliability.
 Audio Frequency Track Vacancy Detection
Audio Frequency Track Circuit is designed as a track vacancy detection system for main
line as well as metro, urban, and suburban railways. The isolation between two tracks is
achieved by means of electrical separation joints.
 Axle Counter
The AZ S 350 U system of Axle Counters offers high economic efficiency by low initial
cost, high reliability and high availability by fault- tolerant evaluation of the pulse count
through multiple axle counting method, space saving compact design, easy
reconfiguring using DIP switches, and interfacing with all interlocking types via parallel
relay interface.
 BPAC
BPAC provides all safety requirements of absolute block working between two stations:
Track vacancy detection and failsafe block information transmission by Axle Counter
system of Siemens AZ S 350 U, safe communication protocol by using the hamming
distance of 9 and all safety circuits wired using K50 Relays having extra features such
as rigid contact carriers with double break contact arrangements.
 Auxiliary Warning System
The Auxiliary Warning System is the economic solution for safer and more flexible
operations; a solution for running more trains in any time interval. The information is

10. [7]
transmitted from the line to the train by this equipment. It continuously monitors the
maximum authorized speed and the braking procedures. Driver gets operating
information for the section ahead and also receives optical and acoustical warnings in
advance.
The system introduces service braking to control the speed with reference to the signal
aspect and helps applying emergency braking in a dangerous situation.
 Point Machines
Point Machine is an electrically motor operated device, which throws a point of railway
track in one direction or the other. The Siemens S 700 K Point Machine is used to throw
points of all types and gauges. It can be used for all points with external locking. Even
derailers and locks, e.g. on lift and swing bridges or lock gates can be operated with this
point machine.
 Thermo Flasher
Mercury Flasher is used for generating a flashing source from a steady input for flashing
indications on the relay interlocking control panel or cabin.
4.1 Working with Indian Railway
Fig 4.1.1: SRAPL successfully commissioned 327 stations across India as of Dec, 18
Siemens is a long-time partner with Indian Railway and this partnership goes back
more than 10 years, since the first introduction of electronic interlocking and signalling
in the main line system. As per the above mention image Siemens have successfully
commissioned 327 stations across India as of December 2018.
In accordance to the most recent figures, Siemens have already commissioned 338
stations with Mk-I system and has 8 projects under various stages. In case of Mk-II
systems they have commissioned 54 stations and have 237 undergoing projects as of 15
July, 2019 in India.

11. [8]
5. Scope of the study
With the widespread use of railway as a means of transporting people and goods
across the nation, signalling and interlocking became an integral part of the railway
system. In the earlier days mechanical systems ruled this system and with the
advancement of electronic systems, slowly the electronic interlocking and signalling
system overran the mechanical systems as they were far too superior and safer than the
earlier system.
So, Electronic interlocking for railway signalling system is the most modern signalling
system used in the railway these days and has a huge scope for advancement in the
coming future, as it is unimaginable to control the number of trains running is India
without this system and the number of trains running daily is increasing on the regular
basis.
Also with the development of dedicated freight corridors and introduction of high speed
trains, this field has huge demand. Not just the main line railway, the suburban transit
systems like metro systems also requires electronic interlocking and signalling and as
of 2019, India is most probably the country with largest number of ongoing metro
projects.
This technology is still at its infancy in India as it’s been just 10 to 12 years since this
system was used in India on a large scale, also it’s a very lengthy process to commission
a station and in case of big stations like Chhatrapati Shivaji Maharaj Terminus (CSMT)
in Mumbai, at the present stage takes 5 to 7 years to complete.
So, there is a huge scope in this sector for the upcoming engineers and trend is not going
to go down as railway is biggest mode of transportation of people and goods in India
and the government is introducing new plans every years to make it much for advance
so that the Indian systems can meetup with the current trend in western countries, which
are far more superior. For example, it’s been less than 6-7 years since Mk-II system was
introduced in India, but in European countries Mk-III system is already in use.

12. [9]
6. Railway Signal
It is commonly said that Rail signal is very much similar to normal road traffic signal
but it’s entirely different from the traffic signal.
Railway signal is the combination of Points/Switches, Interlocking and Signals.
 Similarity in traffic signal and railway signal
Fig 6.1: The road traffic signal and the standard railway signal
As per the general traffic signal we know that RED indication is meant to STOP,
YELLOW is for CAUTION, i.e., cautiously by reducing speed you can proceed if
possible or you stop, and finally GREEN is to GO or PROCEED, and it remains as it is
for Railway signal as well.
 Difference in traffic signal and railway signal
In traffic signal it is a common practice to place RED on the topmost position,
so that people can see it from far away and accordingly reduce the speed, followed by
AMBER/YELLOW light in the middle, which indicates to cross only if unable to stop
safely and if flashing, indicated to cross with caution and GREEN in the bottom
indicates to proceed. These signals indicates the signal for that particular section of the
road or a junction only and is meant for all the vehicles on that road in a particular
direction.

13. [10]
Fig 6.2: Two types of railway signals
Whereas in railway signal these three different coloured lights are placed upside
down in comparison to the road traffic signal. Also in some places 4 signals are used,
i.e., GREEN, Double YELLOW, followed by YELLOW, then RED, or it can be
YELLOW, GREEN, YELLOW and RED. Here ‘RED’ is called ‘Most Restricted
Aspect’ or ‘ON Aspect’ and ‘GREEN’ is called ‘Most Favourable Aspect’ or ‘OFF
Aspect’.
Also, railway signals are always pre-warned, i.e. the loco-pilot knowns what the next
signal is going to be by seeing the present signal, which is not the case in a traffic light
and are called multiple-aspect signalling. They are work for up to 2 to 3 upcoming
signals, depending upon the block section.
6.1 History of Railway signals in India
From the first proposal of railway in 1832 and first train running in 1837 from Madras
for various construction works during British rule followed by India's first passenger
train, between Bori Bunder, Mumbai and Thane on 16 April 1853, which used manual
visual signalling by men, Indian railway has advanced to a whole another level in terms
of signalling.
During the late 1800’s when trains gained popularity in India, still the number of trains
running were very low and usually one train runs in a section in a day. So, the signalling
systems used were very basic. With the number of trains increasing manual mechanical
signalling system implemented and used Mechanical semaphores as means to indicate
signals.

14. [11]
Fig 6.1.1: Semaphore indications for RED, YELLOW and GREEN aspects.
By the late 3rd
quarter of 20th
century, mechanical signalling systems were replaced by
more advanced manual electro-mechanical signalling systems, which used light
indication as a medium for signal indications.
Fig 6.1.2: Modern 3 aspects signal with light indications.
Finally in the early 21st
century the process of using electronic signalling began and in
the recent years automatic electronic signalling is being used in the high density routes.
Indian Railway still uses a range of signalling technologies and methods to manage its
train operations based on traffic density and safety requirements.

15. [12]
As of March 2017, around 2,850 km of the route uses automatic electronic signalling for
train operations – concentrated in high density routes, large cities and junctions.
Remaining routes are based on absolute block electronic signalling with trains manually
controlled by signal men from the signal boxes typically located at stations. Few low
density routes still use manual electro-mechanical signalling methods with
communication on track clearance based on physical exchange of tokens.
Railway primarily uses coloured signal lights, which replaced semaphores and disc-
based signalling (dependent on position or colour). It uses two-aspect, three-aspect and
four (or multiple) aspect colour signalling across its network.
Signals at most stations are interlocked using panel interlocking, route-relay
interlocking or electronic interlocking methods that eliminate scope for human
signalling errors. Also uses track circuiting, and block proving axle counters for train
detection.
6.2 Types of Railway signals
Railway signals can be of different types, like one aspect, two aspects, three aspects and
four aspects signal and depending upon the location of the signal three and four aspects
signal can also have additional direction indicators.
Apart from the above mentioned signal, there is a special signal called ‘Shunt Signal’
and are only placed inside the station section and are used for changing locos, rake
sharing, etc. They have generally very small height and have 2 white signals.
 Two aspects signal
Two aspect signals will only have two signal indications. It can either have Green &
Red or Yellow & Red based on the location where it’s being installed. Two aspect
signals finds their use mainly for two functions, i.e. as loop-line starters and advanced
starters. Both these signals are used to give indications to the loco pilot to start the train
and slowly take the train from station section into the block section.
Fig 6.2.1: Two aspect signal (advance starter) with Green & Red indications.

16. [13]
 Three aspects signal
Three aspect signals will have three signal indications. It can either have Yellow, Green
& Yellow or Green, Yellow & Red based on the location where it’s being installed.
Three aspect signals finds their use mainly for three functions, i.e. as mainline starters,
distant signals and receiving signals.
Mainline starter acts as a starter for the train if it has a stop at that particular station or it
will act as route clear signal for the train that doesn’t stop at that station.
Distant signals can indicate three different indications, i.e. double yellow, yellow or
green. These signals are used in the block section only. Double yellow indicates caution
and proceed, which means if the train is travelling at 110 kmph then the loco pilot will
get to know that next signal will be yellow and the following signal can ask you to stop
so, you need to reduce your speed. Single yellow indicates caution, which means next
signal is going to be red so, loco pilot must reduce the speed to such an extent that he or
she can stop the train gradually. Green is always indicate route clear and the loco pilot
can increase the speed to maximum permissible speed.
Receiving signal, which is also called calling-on signal and will have Green, Yellow
and Red indications along with route indicators and this signal receives the train into the
station section and will always be pushed at least 180 m into the block section.
Fig 6.2.2: Three aspect signal with Green, Yellow & Red indications.
 Four aspects signal
Four aspects signal is also called multi-aspect signal and is used in mainline railway
and is used more frequently in sub-urban railway and has four signal indications,
Yellow, Green, Yellow again and Red. This signal can indicate all kinds of possible
signals used in railway systems and the functions remain same as mentioned earlier.

17. [14]
Fig 6.2.3: Multiple aspect signal with Yellow, Green, Yellow & Red indications.

18. [15]
7. Work-plan with timeline
The 4 weeks internship began on Monday, 3rd
June, 2019 at Siemens Rail
Automation Pvt. Ltd., Bangalore.
Day 1
First day began with reporting to my guide, Mr. Kishore Kumar T.N, presently
designate as Production Manager.
He gave me a brief tour of the facility along with other newly joined interns, showed us
the various sections of the company and took us through common safety measures to be
followed at the time of any emergency like fire.
It was followed by a short duration class on mandatory ESD (Electrostatic Discharge)
safety precautions to be followed while handling all kinds of signalling components in
the Assembly and Maintenance area.
Later in the day, I was provided with schedule for the upcoming 4 weeks, which is as
follows:
Date Department
03-06-2019 to 07-06-2019 Assembly and Packaging
10-06-2019 to 14-06-2019 Testing
17-06-2019 to 18-06-2019 Supply Chain Management
19-06-2019 to 28-06-2019 Designing
Day 2
It was my first day in Assembly and Packaging. I was assigned with Mr. Raghu. He
guided me through the standard procedures followed in the Assembly and Testing area.
It is here, all the modules of WESTRACE Mk-II is assembled and tested before sending
them to the customer.
From 10 AM to 12 noon, I along with newly recruited Engineers belonging to various
departments attended a class on “Basics of Railway Signalling and Electronic
interlocking”, which was conducted by Mr. Vijay Vellanki. This class is supposed to be
held 3 days in a week.
The afternoon session consisted of testing modules. I was shown how the Asset testing
of PIM50 and ROM50 is done, after which I was given certain number of modules for
testing and this work continued till evening.
Day 3
Third day also started with Asset testing of the modules, followed by class from 10
AM. Today we were given a basic idea about, what railway signal means and the main
difference between traffic and railway signal. Then a brief idea was given about the one
book which all the people working with railway must have knowledge about, i.e.
“General Rules and Subsidiary Rules of Indian Railway”. This book covers all the rules

19. [16]
and regulations, power assigned to various railway officials along with the standard
definitions.
In the afternoon after the completion of asset testing, I was shown how the flash testing,
which is a unique test conducted just on ROM50 cards is done, then I was asked to
calibrate the machine using a damaged card and was allotted a batch of cards for which
I have to do the testing.
Day 4
On the fourth day all the interns and newly recruited engineers were taken to the Demo
rooms, where there is an active WESTRACE system. We were given a brief idea about
what the WESTRACE system is, the main difference between Mk-I and Mk-II systems,
all the various cards used in both the systems and finally how signal clearance is done
using an old Control panel which is operated either by the Stations Master or Signalling
in-charge at a railway station.
In the second half I completed the flash testing and after that, the instructor explained
about Functional testing and its use to me. Later he showed the demo of the functional
test using a PIM50 module and explained about Golden unit to which each and every
card is compared and the basic difference in the functional testing of PIM50 and ROM50
modules. Later I was given a set of PIM & ROM cards for my hands on experience.
Day 5
There was no class on signalling on the last day of the week. So, I stared testing the
PIM & ROM modules which I was allotted the day before. After completion, sir
explained me about the final and most crucial testing test done to the modules before
being tested on special jigs made as per the requirement of the RDSO and sent to storage,
this test is called Environmental or SOAK testing. This test is conducted inside a
chamber which replicates the various climatic conditions that the modules have to face
after installation and lasts for 24 hours in the running condition.
After SOAK test, I helped with preparation for RDSO inspection, where the modules
are brought back from storage and are tested again on RDSO jig and finally the serial
number is allotted to the modules as per RDSO nomenclature and the data is uploaded
to the server for future reference.
In the afternoon I was shown how the housing of the WESTRACE system is assembled
and finally the setting up of Installation ID, which is a unique number corresponding to
a particular system located at a place along with the setting up of Housing number. This
worked continued till late evening.
Day 6 & 7
The company doesn’t work on Saturday & Sunday.
Day 8
Second week started today and I was shifted to the Testing department. Mr. Saravanan
Palanisami, Testing Manager handed me various books and documents about

20. [17]
WESTRACE Mk-I & Mk-II systems along with booklets on PCGE, WGM &
MoviolaW, which are various software tools used in designing and testing the signalling
and interlocking systems.
Then he took all the interns to the Demo room, where the actual testing of the completed
system is done before giving the permission for installation. Here we were explained
about the new VDU based systems which are slowly replacing the aging Control Panels.
Later in the afternoon we all were told to sit along with the testing engineers who
explained about the various parameters of software based testing and the method to set-
up the 2 display system for the overall control of a station section, where 1 display is
the for backup.
Day 9
The level of class on Railway Signalling and Electronic interlocking was taken up a
notch. Now the class mainly focused of Electronic interlocking and Signal clearing
procedure associated with it.
Simultaneously the study of GR and WESTRACE system went hand-in-hand. I was also
assigned certain documentation work, where I was asked to convert certain manuals
from Inversys format to Siemens format.
In the second half, the class continued at Demo room, where the concept of hot standby
was introduced and how it is associated with the WESTRACE systems. Later on we
were shown the working of standby system on the active system and explained how the
Mk-II system is advance over the Mk-I system.
Day 10
In the first half, a class was conducted to explain about the Railway signalling, where
we all were given detailed explanation on Station section and Block section, history of
signalling, history of Indian Railway, how signal is given for smooth operation of the
trains, types on signals and railway term used for various aspects.
After the completion of class, in the second half I continued with the documentation
work.
Day 11
Till afternoon, the class on Signalling and Interlocking continued from where it was
stopped yesterday.
In the afternoon interns and engineers were taken to Demo room, to give us all idea
about the various types of cables used in the WESTRACE systems for connecting relays,
housings, field connectivity, etc., earthing of the entire system and finally the drawbacks
of the Mk-I system.
Later, the step-by-step explanation on installation of WGM & MoviolaW on to a new
system was shown followed by a live installation on to system which is being assembled
for dispatch to the on-going project site.

21. [18]
Day 12
It was my last day in testing department. In the morning, I helped testing engineers
with cross verifying RCC and Cross table, afterwards I was sent to Assembly for
understanding about the most crucial module i.e., PM or Processor Module. Person there
explained about various pins and ports of PM, along with its working and importance.
Follow by Asset testing, Functional testing and SOAK testing of the PM modules.
In the afternoon session I was asked to test the PM modules by myself. Since, the
number of PM cards used is very low in comparison to PIM and ROM and also takes
much more time to finish the testing, I was given 5 PM modules. So, I stared with the
testing of PMs and continued till evening.
Day 13 & 14
The office is closed on Saturday and Sunday.
Day 15
Third week started with me shifting to SCM i.e., Supply Chain Management. First of
all, the interns had a group discussion on what the SCM means which was overseen by
a senior staff, who upon conclusion explained us about the basic meaning of SCM and
how it helps the company in smooth operation and gave us an overview of the tasks
carried out by SCM in any company.
In the afternoon session we were told about the advantages of having a separate
department for procuring the components and which also deals with post-sales services.
Later on we were told about sourcing the needed things, how tenders are offered for
procurement, how negotiations are done so that both parties get their fair share of profit
without causing trouble to each other, need for yearly review of the long term tenders,
etc.
Day 16
In the morning class on the signalling continued from where it was left in the last week.
Now the class mainly focused of signalling procedures, aspect sequence, signal
clearance, precedence, etc.
After the signalling class we all went to SCM, where the manager explained us SRAPL’s
procurement policy and guidelines.
In the second half I continued with the documentation work which was allotted to me
last week, by the end of the day, I completed the work and submitted the documents to
testing manager.
Day 17
Today I was sent to the last and most complicated department of the company which
is the Designing. First thing happened there was, a staff handed over a RCC and told me
to go through it and based on the classes I attended in the last 2 weeks, I have to tell him
everything I was able to understand from it.

22. [19]
Later he explained me what a RCC is and process to make a cross table using it, which
is later used in testing stage. I was given the RCC of Salagaon, which is a station
belonging to East Coast Railway and was told to make the cross table using Macros on
Excel sheet.
Day 18
In today’s signalling class we were introduced to SIP (Signal Interlocking Plan), which
is a detailed diagrammatic plan issued by a particular section of railway under which
the station is located and acts as the sole document in preparing RCC and designing the
layout of station. SIP includes track and interlocks position, number of platforms and its
dimensions, location of the various signals and all other necessary details.
Later on I continued with the preparation of cross table of the Salagaon station.
Day 19
In the first half, the class on signalling and interlocking continued and in the second
half I continued with my work on cross table, later submitted the completed table for
cross reference.
Day 20 & 21
The office remained closed for weekend.
Day 22
Today starts the fourth and final week of my internship.
Designing coordinator made a group of 4 interns, including me and handed us a manual
on PCG, which carried the instructions to how to work on WESTCAD, which is a
software tool used to design the Station signal control system. After the completion of
reading, she gave us the RCC and SIP of Raj Athagarh Junction, which is a station in
ECoR division and asked us all to make the cross table and PCG for that station.
In the afternoon we were given a class on how to add logic to the various components
of the station on PCG, which will give indications on VDU based on the input. Later I
started working on PCG.
Day 23
The day started with class about signalling, where the tutor discussed about the various
ways of dispatching trains, different types of railway sections, the mode of
communication between two stations sections and the block section connecting them
and blocking of sections for maintenance purposes.
Later on we continued with the designing task given to us.
Day 24
First of all I discussed my doubts about PCG with the engineer and continued with
designing the station section.

23. [20]
Today in the signalling class, we were taught about the railway safety and inspecting
authority, followed by the steps taken in case of any accident or averted incident and the
natural calamity.
Day 25
Today was my last day in the signalling class, where the mentor discussed about
Subsidiary rules of the South Central Railway and procedure followed while
discontinuing or editing the General Rules, adding subsidiary rules based on the
requirement of the particular division and the people who are authorised to make any
minor or major changes in the rules.
Later we continued with the designing works.
Day 26
Today was the final day on internship. I went to my guide for completing the
documentation work to get the completion certificate. Later on, I continued with the
assigned designing work and by afternoon I submitted the files carrying the design and
cross table to the design coordinator.
In the afternoon, I received my completion certificate from my guide. No further works
were done as it was the last working day of the month and rest of the day continued with
celebrating the birthday of employees, who were born in the month of June, followed
by fun filled games and activities.

24. [21]
8. Experimental work done
8.1 Designing and Testing
Designing and testing of the system control is done in this section. As we all
know hardware remains of no use unless it is supported with software control.
Designing is the initial step in setting up the signalling and interlocking system for a
station.
Designing
The designing work begins based on the Signal Indication Plan (SIP) and Route
Control Chart (RCC), which are the blue print plan and control table issued by the firm
which procured the tender for the work at a station, based on the requirement of the
railway.
SIP
Signal Indication Plan carries the complete details of a station i.e. tracks,
dimension on the platforms, station master hut, location of pols supporting Over Head
Electric (OHE) cables, locations of where the signals and points will be installed, etc.
RCC is an elaborate table, which carries the details of the signals and points, their
inter-relations and the details of the route lock.
Fig 8.1.1: Signal Indication Plan (SIP) of Chandra Fort (CAF)
9.
Based on the input from SIP, using a software tool named PC Graphic Editor (PCGE)
the yard layout for the station is designed and the logic to each and every part is
individually stored and then the PCGE design is converted into WESTRACE
Graphical
Simulator called WESTCAD format and saved in both the formats, as future editing if
needed can only be done on PCGE and for testing WESTCAD format is required.

25. [22]
Fig 8.1.2: Completed PCGE yard layout of Chandra Fort (CAF)
The WESTCAD file which is saved in .gpc format and can be opened using Dummy
WestCAD just for checking the resolution and any visual error only. In order to run
the logic testing a special software names MoviolaW is used and the cross reference
testing is done based on the Cross Table which is generated using the details from
RCC.
Fig 8.1.3: Completed WESTCAD yard layout of Nandini-Langunia (NNNL)
RCC
RCC stands for Route Control Chart and is an elaborate table, which carries the
details of the signals and points, their inter-relations and the details of the route lock.
RCC is used to generate cross table, which is used for testing in WestCAD.

26. [23]
Fig 8.1.4: Front page of Route Control Chart (RCC) for Chandra Fort (CAF)
Fig 8.1.5: Example of an edited Route Control Chart (RCC)
10.
From the given RCC, Macros tool is used to generate the cross table by entering
the all the routes and the locking sections associated with that route followed by points
and their intersections on to separate excel sheets and running the macros logic stored
in CONVERSE-VER.02, which is a special excel files generated on GCSS.

27. [24]
Fig 8.1.6: Completed cross table of Chandra Fort (CAF)
Note:
In the above given cross table various marking indicates the following:
Indicates ‘Allowable signal’
Indicates ‘Point lock’
Indicates ‘Route lock’
Testing
After the completion of designing of PCGE layout, WESTCAD layout, logic
pupation and completion of cross table. Now, it’s time for rigorous testing of software
and Visual Display Unit (VDU) on Test rack before integration on to the station rack.
Testing of the system is divided into 4 main parts:
1. Cross-checking using Cross table
2. Cross verification using RCC
3. Negative testing
4. Signal clearance testing
Cross-checking using Cross table is firstly done to verify whether the generated cross
table is correct or not. Afterwards the route clearance on allowable signal is checked,
then the route lock and point lock is verified.
Cross verification using RCC is done to verify that no point or route is left out and in
case of route clearance all the required points are locked.
Negative testing is performed after giving a route lock, to check that once a route is
locked no points and signals associated with that route is changeable. So, that no route
failure takes place.
Finally the signal clearance testing is done for all the possible routes in the station
section and the block section located nearby.
P
X

28. [25]
All the above mentioned tests are repeated four to five times by different testing
engineers and results are verified with RDSO standards and one verified by the testing
manager, the system software is now ready for Graphical Simulation (GSIM).
Fig 8.1.7: Myself performing the cross verification using RCC for Patharkhola Jn. (PKB)

29. [26]
8.2 Production and Testing
Production area consists of Assembly and Testing, which is an interlinked process.
No components are produced by the company, it only design the product as per the
requirement of the buyer. All the components are designed are simulated and then
outsourced for manufacturing.
SRAPL has two products in its arsenal i.e., WESTRACE (Westinghouse Train Radio
Advanced Communication Equipment) Mk-I and MK-II.
Once all the components are ready, they reach at the facility and are stored.
The production and testing area is compatible to Safety Integrity Level 4 (SIL-4), which
includes Anti-Static floors, all the table, chairs, etc. are covered with Electrostatic
Discharge (ESD) material, it is mandatory for every person to wear ESD foot wears
before entering the area and to wear ESD gloves and wrist strap connected to ground
while assembling the modules. All these precautions ensure the safety of the person and
the electronic components being assembled from static charge developed by human
body.
At the Assembly and Testing area, all the components are brought and the module
assembly begins. Only WESTRACE Mk-II modules are being produced now. The entire
procedure is divided within 6 stations. Which are as follows:
1. Inward Inspection
2. Asset Programming
3. Flash Testing
4. Functional Test
5. SOAK Test
6. Functional Test on RDSO Jig

30. [27]
Fig 8.2.1: Flow-chart representing the procedures to be followed in production and testing
area

31. [28]
Inward Inspection
 Here all the components are unpacked from their packaging, the PCB sets are then
visually and physically inspected for any damage and are transferred to ESD boxes
to prevent from static charge that can damage the electronic components and the
face plate, housing, etc. are separately stacked.
 The upper switch and bottom or power switch is connected on the face plate.
 Then the chipset is taken one by one and the face plate is connected to it and the
lower half of the housing plates is attached.
 The module is now ready for next stop.
Asset Programming
 Here the module is connected to the asset programmer and the serial number,
revision number, module statistics and part number, which are pre-loaded in the
memory by the manufacturer are verified and based on the current revision and stat
if change is needed is also done here, then rest of the assembly is completed and
sent to next station.
 For PIM-50 and ROM-50 it just takes 3 to 5 minutes, but in case of PM it takes 18
to 20 minutes for the test to complete successfully.
Fig 8.2.2: Asset programming and testing unit

32. [29]
Flash Testing
 Flash test is done only to the ROM-50 module, as they are the output modules and must
withstand extremely high voltage.
 In this test all the 8 ports of the ROM module is exposed to 2000V for 10 seconds
individually and the current must not go above 0.6µA, all checked for any kind of
problem and then sent ahead.
Fig 8.2.3: Flash testing unit
Functional Test
 Functional test is where each end every module is tested on different parameters,
which varies for PIM, ROM and PM.
 Here the modules are connecting to the jig and compared with KGU (Known
Golden Units). All the ports, components, indicators, etc. are tested and checked,
also the changeover between the primary and standby module is done, later on sent
for Environmental testing.
SOAK Test
 SOAK test is the environmental testing. Here the modules are connected as per the
field condition and tested for 24 hours at temperatures ranging from -20⁰C to +70⁰C.

33. [30]
 The test begins from room temperature i.e. 25⁰C, then the temperature is slowly
reduced to -20⁰C by taking 1 minute for each value and once the temperature
reaches -20⁰C, this temperature is maintained for 4 hours. Later on the temperature
is gradually increased till +70⁰C and then that temperature is maintained for 4 hours
as well. This cycle is repeated for 24 hours and the statistics are monitored and the
data is stored.
Functional Test on RDSO Jig
 This is the final testing phase, where all the modules are testing Jig, made as per the
needs of RDSO (Research Design and Standards Organisation). This test is
conducted twice. Once the module is assembled, basic testing is completed and
sending them to the storage and secondly before despatching to the concerned
buyer.
Once all the above mentioned tests are passed by a module, a slip indication the
passing of all the tests is stickled at the back, then it is given the permanent label
indicating the serial number, time and year of manufacturing and also an OK Qualified
sticker is placed by the quality control and the finished modules are sent to storage.
Later on before send the modules to the various divisions of Railway, a label
indicating the RDSO serial number is also applied to future reference.
Fig 8.2.4: Myself testing the PIM cards on RDSO jig before despatching

34. [31]
8.2.1 Products
In India Siemens is dealing with two variants of Electronic Interlocking system, i.e.,
WESTRACE Mk-I and Mk-II.
 Mk-I was the first Electronic Interlocking system introduced by Siemens about 15
years back and have successfully implemented in 338 places and at 8 places, work
is underway at various levels as of June, 2019.
 Mk-II is a major upgrade over Mk-I system and is being used in India from the past
5 to 6 years and is already installed at 54 locations and work is undergoing for 218
locations spread all over India, as of June,2019 and it includes new stations as well
as upgrading the oldest Mk-I installations.
a) WESTRACE Mk-I
WESTRACE Mk-I is the first generation of railway signalling and electronic
interlocking system made initially by Inversys, but eventually the entire system was
bought by SIEMENS Mobility and ended up as the first electronic system used in
Mainline Indian Railway.
Since this was the first of its class so, it was very bulky and had separate module for
each and every purpose, the overall system was very complicated and was difficult to
maintain and service due to higher number of cards. Also each and every empty slot
needs a blanker card.
Following are the two types of card in the WESTRACE Mk-I system:
1. Vital Cards
2. Non-vital Cards
Following are the main parts of Mk-I:
1. Output Power Card (OPC)
2. WESTRACE Network Communication Module (WNCM)
3. Vital Parallel Input-Output Module (VPIM)
4. Vital Relay Output Module (VROM)
5. Power Supply Unit (PSU)
6. Filter cards
7. Blanker
8. WestCAD
Output Power Card (OPC-24)
The Output Power Card is output power supply card for the Mk-I system modules.
OPC takes 24V DC as its input supply and gives out 50V DC output supply. Its main
purpose is for change over during failure and to ensure the overall safety of the
modules. It is connected in series with the OPC Relay, which acts as the safety
mechanism. Pin 12 &13 are connected to the NC Relay.

35. [32]
The booting time for this module is 3.5 minutes for the main system followed by 5
minutes for the hot standby system. The 1.5 minute gap is pre-set so that the system
can differentiate between the main and standby in case of booting after shutdown or
failure.
Fig 8.2.1.1: OPC-24 card.
WESTRACE Network Communication Module (WNCM)
WESTRACE Network Communication Module is the EEPROM of the Mk-I
system. WNCM is a stack of 2 cards fixed together, which includes Vital Logic Card
(VLC-6) and Network Communication Diagnostics Card (NCDC).
The VLC-6 is the card where the application program is installed and it also executes
the program for the system operation. The VLC-6 carries 4 AM29F010B ICs.
Whereas the NCDC is the error detection card in terms of the communication between
system and the associated parts in the field. NCDC carries 2 ports on board, called
serial port and production port. Since the NCDC & VLC is stacked together so, the
vital logic is loaded on to the production port of the NCDC.

36. [33]
Fig 8.2.1.2: WNCM card.
Vital Parallel Input-Output Module (VPIM-50)
Vital Parallel I/O Module also has 2 cards stacked together, these cards include Vital
Parallel Input Output Digital Board (VPIODB) and Vital Parallel Input Module with
Analog Board (VPIMAB).
VPIM is rated at nominal voltage of 50V DC, but it can operate without any issue in
between the input voltage of 30V to 100V DC. In order to make the card fail safe and
to make it unaffected by surrounding voltages, VPIM will not respond to 10.5V and
less, which can occur due to disturbance from surrounding and will not detect any input.
VPIM also carries a 50mA fuse for additional safety and prevents the card from any
major problem and can be easily replaced on-site by any maintenance personal

37. [34]
Fig 8.2.1.3: VPIM-50 card.
Vital Relay Output Module (VROM-50)
Vital Relay Output Module is also a stack of 2 cards, these cards include Vital Parallel
Input Output Digital Board (VPIODB) and Vital Relay Output Module with Analog
Board (VROMAB).
Similar to VPIM, VROM also has a nominal operating voltage of 50V DC but can
operate at voltages between 42V and 60V. It can operate in the current range between
0.5A and 500mA and if the current exceeds this limit, associated relay will operate and
isolate the card.
VROMAB also operated between 42V and 60V, with nominal voltage of 50V, but each
pin can withstand up to 80V DC, because voltage can fluctuate easily which signal
change and the VROMAB is the most effected card.

38. [35]
Fig 8.2.1.4: VROM-50 card.
Blanker
Unlike the new Mk-II system, Mk-I system needs continuity modules where the slot
is left open in the housing, in order to avail the system continuity, otherwise there will
be a discontinuation in the system operation. Such continuity modules are called blanker
or dummy card. Blanker is a card with 96 pins.
This is also one of the main drawback of the Mk-I system.
Power Supply Unit (PSU)
Power Supply Unit is the power supply monitoring card. Because Mk-I system needs
wide range of voltages as every other card operates are different voltage. So, PSU
supplies and monitors the power supply to the system.
PSU uses a 5 LED indication, which indicates the following:
 -> +5V DC
 -> +12V DC
 -> -12V DC
 -> +12V DC
 <- +24V DC

39. [36]
Fig 8.2.1.5: PSU Card.
Filters
Filters are the additional circuitry added to the Mk-I system to improve its working
efficiency by cancelling out the harmonics and noise generated in the system due to
surrounding instruments.
The filter used in the system is called as the Production Filter Module (PFM) and there
are 4 different PFMs, one for each module. They are as follows:
1. Higher Output Power Card Production Filter Module (HOPC PFM)
2. Network Communication Diagnostics Production Filter Module (NCD PFM)
3. Vital Parallel Input Output Module Production Filter Module (VPIM PFM)
4. Vital Relay Output Module Production Filter Module (VROM PFM)
HOPC PFM
Higher Output Power Card Production Filter Module is the filter used for OPC.
It has a 19 pin arrangement and is placed in the back of OPC. Two power supply of 24V
DC is fed to pin 1 and 2. Pin 12 and 13 are connected to the back contact from relay and
pin 14 and 15 delivers 50V DC output.

40. [37]
NCD PFM
WESTRACE Network Communication Modules filter card is called the Network
Communication Diagnostics Production Filter Module. It continuously checks the
communication between the main and standby system. NCD PFM carries two Optic
Fibre Connector (OPC) ports names Tx and Rx and is present in both the systems. The
ports are connected in such a way that Tx of main is connected to Rx of standby and Rx
of main is connected to Tx of standby. These connections ensure that the hot standby
system constantly receives the details of main system operation so that the standby
system can immediately take over from mains in case of any technical glitch.
VPIM PFM
The Vital Parallel Input Output Module Production Filter Module is used in
accordance with VPIM-50 card. This filter consists of 24 pins arrangement. This is used
to receive input from the field and there are 12 sets of input available and pins 1 to 12
are the positive terminals and pins 13 to 24 are negative terminals. Following are the
possible inputs:
Input 1: Pin 1 & 13
Input 2: Pin 2 & 14
Input 3: Pin 3 & 15
Input 4: Pin 4 & 16
Input 5: Pin 5 & 17
Input 6: Pin 6 & 18
Input 7: Pin 7 & 19
Input 8: Pin 8 & 20
Input 9: Pin 9 & 21
Input 10: Pin 10 & 22
Input 11: Pin 11 & 23
Input 12: Pin 12 & 24
VROM PFM
The Vital Relay Output Module Production Filter Module is associated with VROM-
50 and is used to give command to the instruments and equipments in the field. The
filter has 19 pins and can deliver 8 sets of output. Pins 1, 4, 6, 8, 10, 12, 14, 16, 18 are
the positive terminals and Pins 2, 5, 7, 9 , 11, 13, 15, 17, 19 are the negative terminals.
Also pin13 is a dummy pin. The arrangement is as follows:
Pin 1 & 2: -> 50V DC
Pin 3: Dummy pin
Pin 4 & 5: Output 1
Pin 6 & 7: Output 2
Pin 8 & 9: Output 3
Pin 10 & 11: Output 4

41. [38]
Pin 12 & 13: Output 5
Pin 14 & 15: Output 6
Pin 16 & 17: Output 7
Pin 18 & 19: Output 8
Housing
Housing is a Vital Logic Equipment (VLE) and has a backplane attached to it. Each
Mk-I housing carries 16 slots and is cards are always placed from right to left.
Following is the Card play arrangement:
 Slot 1: Blanker or Dummy
 Slot 2: OPC-50
 Slot 3 & 4: WNCM
 Slot 5: VPIM-50 or VROM-50
 Slot 6: VPIM-50 or VROM-50
 Slot 7: VPIM-50 or VROM-50
 Slot 8: VPIM-50 or VROM-50
 Slot 9: VPIM-50 or VROM-50
 Slot 10: VPIM-50 or VROM-50
 Slot 11: VPIM-50 or VROM-50
 Slot 12: VPIM-50 or VROM-50
 Slot 13: VPIM-50 or VROM-50
 Slot 14: VPIM-50 or VROM-50
 Slot 15: Blanker
 Slot 16: PSU-24
Following are the conditions to be satisfied while installing an Mk-I system:
 An Mk-I system can have a maximum of 4 housings only.
 1st
housing can have up to 5 input or output cards.
 2nd
to 4th
housings can have maximum of 7 input or output cards.
 In 2nd
to 4th
housings only slot 15 carries blanker and slot 16 is PSU and rest of the
slots can carry any cards.
 Interconnection of maximum 16 systems is possible.
 So, at maximum a system can have 26 input or output cards due to one WNCM.
 Each housing has a motherboard with 3 terminals, 5V-C-OV and 4 links. These
links are terminals are used so that system can differentiate the housings.

42. [39]
Following is the setup:
Link 1 Link 2 Link 3 Link 4
Housing 1 0 0 1 To standby
Housing 2 0 1 0 X
Housing 3 1 0 0 X
Housing 4 1 1 1 x
Note:
Terminal arrangement to achieve 0 and 1:
 Communication between housings is parallel in nature and is carried out using EC
cable and is 3 types based on the length and are as follows:
 EC-1: 300mm
 EC-2: 500mm
 EC-3: 700mm
b) WESTRACE Mk-II
WESTRACE Mk-II Electronic Interlocking system is a very modular and versatile
system. This system is designed to act in plug and play method, i.e., the modules does
need to be programmed individually, the programmable logic is stored in Back Planes.
So, even in case of any problem with any module, that particular module can be removed
and replaced without affecting the overall system, which was not possible in the earlier
variant.
Major components of the WESTRACE Mk-II system are as follows:
1. Processor Module (PM)
2. Remote SMB Adapter (RSA)
3. PIM50 (Parallel Input Module 50V DC)
4. PIM12 (Parallel Input Module 12V DC)
5. ROM50 (Relay Output Module 50V DC)
6. ROM12 (Relay Output Module 12V DC)
7. LOM110 (Lamp Output Module)
8. TCOM (Track Code Output Module)
9. SOM24 (Signal Operating Module)
10. SOM110 (Signal Operating Module)
11. SM-MAU (Signal-Mode Media Adapter Unit)

43. [40]
12. TCOM Filter
13. 5-slot coated backplane
14. 5-slot back plane
15. 10-slot coated back plane
16. 10-slot back plane
17. PM back plane
18. Housings
19. Cables, terminators and shields.
The entire system went through lots of updates in last decade and most of the
components in the WESTRACE Mk-II is not suitable for Indian market. So, Indian
version of WESTRACE Mk-II constitutes of 5 main components for Main line system.
They are as follows:
1. Processor Module (PM)
2. Processor Module Back Plane (PMBP)
3. Parallel Input Module (PIM)
4. Relay Output Module (ROM)
5. 10 slot Back Plane (Housing)
Along with the above mentioned components metro system uses an additional module
called Lamp Output Module (LOM).
Processor Module (PM)
Processor Module is the heart of the Electronic Interlocking system. The PM
constitutes of 3 microprocessors, two of which carry out the system’s vital logic
processing using diverse redundant channels. The third microprocessor manages
communications and diagnostics.
The PM executes the interlocking logic as defined in the Application Data. It controls
the other modules and manages communications with other vital systems for control and
system diagnostics, also PM has the capacity to support up to 64 PIM50 or ROM50 or
combination of both, but it is a standard practice to use only a maximum of 38
input/output cards.
PM works on dual-input 24V DC supply and is normally placed in slot 1, hot standby
PM is placed in slot 2 in each of two co-located housings. PMs can only be installed in
slots with PMBP fitted.
A WESTRACE interlocking system must have at least one PM. Most systems only need
one PM or a hot-standby pair of PMs. The system can have multiple PMs.
Each PM addresses up to:
 64 housings (includes the one in which it resides)
 64 SMB interfaces, 2 local SMB interface (numbers 1 and 2) and 62 remote SMB
interfaces (interface numbers 3 to 64).

44. [41]
 128 modules in any mix (PIMs, ROMs, LOMs, etc.) including the Pm, in remote or
local housings. A hot-standby pair of PMs counts as 2 modules, leaving addresses
for up to 126 I/O modules.
Fig 8.2.1.6: Front and back view of Processor Module (PM)

45. [42]
Fig 8.2.1.7: PM front panel indicators

46. [43]
Fig 8.2.1.8: Chipset inside the PM

47. [44]
Processor Module Back Plane (PMBP)
Processor Module Back Plane is the special port placed in the lower back of the
housing to place the PMs and the PMBR also carries an inbuilt memory to store vital
logic and additional ports are there to install the software on to the system.
The PMBP provides:
 Two Ethernet network ports, used by the PM for external communications.
 Flash memory used by PM to store application data.
 Two PM hot-standby connectors used to interconnect PMs in a standby pair, one
Ethernet and one 4 pin plug.
Fig 8.2.1.9: Inward section of the PMBP
Fig 8.2.1.10: Back section of PMBP
Parallel Input Module (PIM)
Parallel Input Module monitors voltage on its electrically isolated input terminals and
provides a logic state to the PM. It rejects AC noise on the input (exceeds AC rejection
requirements for traction immunity), and has a configurable pick delay.
PIMs receive inputs from external devices. PIM50 has 12 inputs. Two PIMs of the same
type may be connected in hot standby for improved availability, but giving hot standby
to each and every PIM will increase the size of the overall system and makes it much
more complex. So, to avoid this problem, the system is provided with few excess PIM
modules, which takes over as soon as any PIM faces any issue and accordingly the
troubled module can be replaced later without causing any signal loss.

48. [45]
Fig 8.2.1.11: Front panel view of PIM with indications
Fig 8.2.1.12: Front and back view of PIM

49. [46]
Fig 8.2.1.13: Chipset inside the PIM

50. [47]
Relay Output Module (ROM)
A Relay Output Module accepts logic states from the PM and applies voltage to its
isolated output terminals to follow these logic states. It can be said that, whenever a
station master or signalling officer gives command to clear a signal, the signal is send
to PM, which processes the signal and send commands to ROM, which eventually gives
appropriate command to the respective instruments like signal indicators, point
machines, etc.
Fig 8.2.1.14: Front panel view of ROM with indications
Fig 8.2.1.15: Front and back view of ROM

51. [48]
Fig 8.2.1.16: Chipset inside the ROM
Lamp Output Module (LOM)
A LOM accepts logic state from the PM and switches and externally-supplied
voltage to its output terminals that follow this state. Individual LOM outputs may be
configured as steady or flashing. Flashing is synchronised within a module but not
between modules.
Configurable lamp proving currents can be individually set on each output and the
resultant logic state provide to the PM.
There are six 110V AC outputs per LOM, 600 mA max. Each output switches an
external AC lamp supply to the nominated device. Outputs are double cut when off.
The LOM is the interface between WESTRACE and signalling lamps. LOM outputs
directly drive signal lamps and other equipment. The output may be steady, flashing or
off. The flash rate and mark space ratio are configured using GCSS.

52. [49]
NOTE: Only lamps on the same LOM are synchronised when flashing.
The LOM modules have 6 outputs.
LOMs detect lamp outputs current leakage. Where the leakage is greater than the
configured value, the LOM shuts down output to the lamp. Check for current leakage
if individual lamp outputs shutdown.
Fig 8.2.1.17: Front and back view of LOM

53. [50]
Fig 8.2.1.18: Front panel view of LOM with indications
Housing
A housing comprises a full 19” or half 19” 6RU housing, a backplane and connectors
to accept other WESTRACE modules. WESTRACE Mk-II housings are typically
installed in 19 inch racks.
Available housing:
 10-slot – a full 19” width housing that holds 10 modules;
 10-slot – two half 19” backplanes that hold 5+5 modules.
Other housings have been developed for particular installations, e.g. 4-slot, 5-slot
“compact housings”.
Eventually multiple housings are connected by cables that extend the Serial Module
Bus.

54. [51]
The number 1 housing or top left housing (when viewed from the front), by
convention, contains the PM in slot 1. By convention:
A hot standby pair of PMs in the same housing go in slot 1 and 2
A hot standby pair of PMs in two housings go in slot 1 of each housing.
PM slots have PM backplanes fitted. This backplane contains the Ethernet network
port, Flash memory, and PM hot standby connectors (used to interconnect the PMs in
a hot standby pair). The flash memory stores the application data so that PMs and
RSAs can be swapped out without the need to reload the application data.
The remainder of housing 1 and any other housings can be populated with specific
functional modules.
Fig 8.2.1.19: Front and back view of Housings

55. [52]
Fig 8.2.1.20: Back view of a 5-slot housing with PMBP installed
Fig 8.2.1.21: 10-slots housing and panel dimensions

56. [53]
Fig 8.2.1.22: Back view of a blank housing
Note:
As of July, 2019 SPARL has commissioned WESTRACE Mk-II system at 54
locations all over India and there are 218 ongoing projects.
So, in order to differentiate each and every system Installation address is provided.

57. [54]
8.2.2 Installation address
Installation address is a 6 digit number self-generated by the GCSS while designing
and is unique to each and every station. Installation assembly details constitutes of 3
parts, i.e. Address and Configuration Link Jumpers, True Housing Address and
Compliment Housing Address.
This data is stored on to the housing manually by cutting resistors. The Address and
Configuration Link Jumpers remains same on all the housings in a system but True
Housing Address and Compliment Housing Address is based on the housing number.
Fig 8.2.2.1: The resistor pairs where installation address in stored
Example:
Installation Name: Mahdeiya
Installation Address: 610491
-----------------------------------------------------------------------------------------------------------------
Installation Assembly details
Address and Configuration Link Jumpers
INST_0
INST_1
INST_2
INST_3
INST_4
INST_5
INST_6
INST_7
o---o
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R8
R9
R10
R11
R12
R13
R14
R15
INST_8
INST_9
INST_10
INST_11
INST_12
INST_13
INST_14
INST_15
o---o
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R16
R17
R18
R19
R20
R21
R22
R23
INST_16
INST_17
INST_18
INST_19
INST_20
INST_21
INST_22
INST_23
o---o
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R24
R25
R26
R27
R28
R29
R30
R31

58. [55]
True Housing Address
Housing 1 Housing 2 Housing 3
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
Housing 3 Housing 4 Housing 5
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
Compliment Housing Address
Housing 1 Housing 2 Housing 3
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
Housing 3 Housing 4 Housing 5
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7
HSG_0
HSG_1
HSG_2
HSG_3
HSG_4
HSG_5
HSG_6
o---o
o---o
o---o
o---o
o---o
o---o
o---o
R1
R2
R3
R4
R5
R6
R7

59. [56]
Power Supply
WESTRACE operates from one or two 24V DC, uninterruptable, smooth, supplies.
The input voltage range is suitable for operation from a float charged battery.
Typically two supplies are used, derived from separate sources to give high
availability.
Each housing requires its own power connection.
WESTRACE systems can also require:
 50V DC signalling supply to power ROM50 modules and to input to PIM50
modules.
 110V AC supply for the LOM110 modules to power signalling lamps.

60. [57]
9. Conclusion
I have successfully undergone four weeks training in ‘Electronic interlocking for
railway signalling system’ by Siemens Rail Automation Private Limited (SRAPL),
Bangalore. In this four weeks training, I have learnt about Railway signalling and
advanced electronic interlocking based signalling mechanisms being implemented in
the mainline and sub-urban railway systems to make sure trains run smoothly without
any delay or any kinds of accident takes place within the system and even if any accident
takes place by chance, it must happen on the safe side.
Apart from railway signalling, the most import thing that I learnt about is how a control
system within station section and block section is setup from scratch. The importance
of the system i.e. WESTRACE Mk-II and how it helps in reducing the dependence on
human actions for signal clearance, which will eventually eradicate the human error.
Most importantly electronic interlocking in railway signalling will eliminate the direct
and indirect railway accidents to a certain extent and will also reduce the requirement
of manpower. Eventually the manpower will only be required to monitor the system and
for annual maintenance.

61. [58]
10. Reference
 General Rules for Indian Railway with Subsidiary Rules and Special Instructions
of South Central Railway 2008 (including A.S. No. 14)
 SIEMENS First-line Maintenance Manual Trackguard WESTRACE Mk1
WRTOFLMM Issue 12.0
 SIEMENS First-line Maintenance Manual Trackguard WESTRACE Mk2
WRTOFLD Issue 8.0
 Handbook on Basic Concepts of Railway Signalling
 Inversys Training Course Manual PC Graphic Editor Design Issue 2.1
 Inversys Training Course Manual WESTRACE Graphic Simulator User Design
Issue 2.4
 GCSS Revision 10.0.0
 RSDO approval documents for Mahdeiya (MHDA) – East Central Railway by
SRAPL – 12:21:38, Tue, May 07, 2019