India’s colourful signalling aspects

The Institution of Railway Signal Engineers (IRSE) ventured to New Delhi in October for its 2010 convention. For many, this was a first experience of the sub-continent; no-one quite knew what to expect. Delhi’s pollution and traffic chaos gave a foretaste of what was to come.

Day One centred on technical papers, firstly with overviews of Indian Railways given by high ranking ministry and railway officials. India has the world’s fourth largest railway with 63,000km of route, mainly on the broad gauge of 5’6” with much of it electrified, and 1.2 million employees. In signalling terms, it has 4,500 interlockings, 2,000km of automatic block sections and 900km equipped with the Indian version of TPWS. Seemingly impressive, the Indian signalling fraternity is being called upon to deliver capacity enhancements, safety improvements and increased operating reliability. With the dignitaries departed, the convention then got down to the engineering reality with the Indians telling how they do things and the emerging technologies with which the world is tempting them.

Two novel systems

Various presentations of Indian S&T systems gave a mixed picture. Signalling technology looks dated compared to European standards – big interlockings still using relays. A new system, installed in 2008, at Delhi’s main station replaced a 1982 route relay interlocking but was more a like-for-like exercise. High speed has yet to happen with 30kph turnouts being the norm. Design work and project management are done largely in house. However, as a result of some serious accidents, two novel protection systems are being introduced.

The first is IR’s version of Britain’s TPWS, more akin to ERTMS Level 1, and developed by Ansaldo. The two routes equipped so far – Delhi North and South – have encountered problems due to temperature swings, dust ingress, power supply outages and voltage trips. Nevertheless, this is a step on the road to providing a low-cost ATP that can be bolted on to existing signalling.

The other is an Anti Collision Device (ACD) using satellite positioning information and local VHF radio distribution. Developed in India by Konkan Railways Ltd, the system works by a fixed locomotive device linking to the satellite and distributing position data to an ‘end of train device’, stations, level crossings and the train guard. Independent of the signalling, the system is used for train integrity, level crossing activation, speed supervision and station awareness in foggy conditions. A tunnel-mounted repeater system ensures an end-to-end train signal throughout the journey. Around 3,300km of route are operational but, to be fully effective, all trains must also be fitted. End-of-train devices are battery powered with magnetic clamps and, should a train derail, they will radiate warnings to all other trains in the vicinity.

Delhi's relay room
Delhi's relay room

Telecommunication systems are much more progressive and compare well to European equivalents. Technology includes –

• 37,700km of fibre cable laid with SDH & PDH transmission plus copper quad cable

• data network for nationwide ticketing and reservation

• train tracking (SIMRAN) based on GSM-R and GPRS

• track-to-train radio still largely VHF with selective calling but with GSM-R being rolled out

• a centralised digital PA system activated by train movement or from operational control centres

• nationwide clock system with a caesium master

• SCADA for monitoring of non-traction power, lifts and escalators, and tunnel ventilation

• WiMAX networks giving communication of 5km around stations and depots

• soft switch for nationwide voice traffic

• data logger for train charting with time/distance graphics.

Much of the telecommunications infrastructure has been transferred to a separate company, Railtel, similar to British Rail Telecoms here in the Nineties. This company trades with the railway regions but does not have a monopoly. It is progressing a growing IP network and uses both satellite and radio links to increase reliability and availability. A 24-hour maintenance organisation manages faults, diagnostics and configuration control. It is also allowed to sell capacity to third parties.

Promoting technology in India

The big S&T suppliers saw the opportunity to promote new systems and products to Indian Railways. Those making a pitch were –

• GE Transportation: full ATP for passenger rail safety, overlaid on existing signalling using GPS and WiFi receivers, as used in Italy with SIL4 certification and no on-track devices.

• Bombardier: the merits of CBTC (communications-based train control) for modern metro operation, capable of overlaying on the existing signalling, using 2.4GHz radio transmission and position monitoring by transponders plus odometry. It is in service on the Madrid Metro and some lines in Delhi.

• Motorola: the choice for future wireless technologies both in narrow and wide band with multi-usage for both safety and non-safety applications.

• Nokia Siemens: the evolution beyond GSM-R, missing out the current 3G standard and going direct to LTE (Long Term Evolution). The claim made is that this will be a simple migration, needing only one additional module to each base station and giving a huge data capacity, including broadband to passengers at train speeds up to 350kph.

Quite what the Indians will make of these offerings is a matter of conjecture. They perhaps have more urgent matters on their minds.

Technical visits

Viewing the local infrastructure is all part of an IRSE convention experience. This shows up the reality of the railway and can sometimes be a big contrast to what the presentations portray.

From what was seen, the telecommunications matched expectations with fibre cabling, transmission, radio and IT systems all having seen significant investment. A large satellite dish and an 80m tower were visual evidence of network integrity and diversity. The need for robust nationwide communication is crucial to link the 16 zone HQs and 66 divisional HQs.

The data centre for passenger reservation and ticketing was state-of-the-art. The idea is to change cultural attitudes to rail traffic. Booking a journey can be undertaken online or at stations. Unreserved tickets can be bought three days in advance with no guarantee of a seat. Several thousand transactions take place daily from five IT centres. The resilience of both the computing and transmission networks make failures a rare occurrence.

By contrast, Siemens’ ‘new’ interlocking and control room, dating from 2008, looked very jaded – more akin to a Sixties-vintage BR power box. There was no visible train describer so regulation must be rather difficult. It was a surprise to many that Indian Railways have not embraced solid state interlockings and VDU operating screens more readily. Perhaps this portrays the national caution of their signalling engineers.

The worst impression from the visits was the cleanliness of both equipment and operating rooms. At best these were scruffy, at worst verging on filthy. An operational control centre was being rebuilt around the live equipment with dust and dirt getting into the screens, keyboards and equipment racks. A cultural change is needed here as equipment life is being jeopardised by the lack of a clean, disciplined environment.

Train services

No visit to Delhi can be complete without a trip to the Taj Mahal at Agra, some 200km distant. Electing to take the group by service train was probably a mistake – the 0615 was some 30 minutes late from the carriage sidings and nearly one hour late away. The seat reservations worked fine but the standard of the train, lavatories and catering provision was something of a culture shock. With timings gone to pot, the Taj Mahal and Agra Fort visits were the priority – both were truly spectacular. This left little time to see the local TPWS installation but it was viewed at a trackside location by torchlight!

The return home was even more fraught with the 1930 train announced as 1½ hours late. Even after departure, the journey took far longer than the advertised two hours, with seemingly miles and miles at near walking pace. Arrival in Delhi was at 0100! If the Indians were intent on impressing the western world with their train services, they failed miserably.

Passenger Info sign
A passenger information sign at Agra Station

The Delhi Metro

Strangely, Delhi’s main line railways carry only minimal commuter traffic – passenger services being predominantly long-distance daytime and overnight trains. With growing traffic congestion, the only solution has been to build a Metro network and this is the city’s showpiece.

Construction started in 1998 with the first line of 8.5km and six stations. This has grown to six lines totalling 130km – with 44km underground – serving 144 stations. Five lines are Indian broad gauge but the latest is standard gauge – this will be adopted for all future additions. Simple economics dictate that infrastructure and trains are much cheaper if they come from a factory as a standard product.

Although initially designed by Japanese consultants and delivered with Korean infrastructure, Alstom control systems and Japanese trains, more recent lines have widened the supplier base. Line 6 is equipped with Bombardier trains and systems, and opened just in time for the Commonwealth Games, carrying 40,000 people in the first hour. Just missing the Games is the new 22.7km line to the airport which will feature 130kph running.

The Metro has all the usual modern features and some surprising ones as well –

• 25kV overhead electrification with rigid conductor beams in underground sections

• ballastless tracks and integration of points into long-welded rails

• 530 broad gauge and 44 standard gauge trains – other than prototypes, all were built in India

• regenerative braking

• two control centres, each with a 90km capability

• electronic CBTC signalling (which initially struggled to cope with Delhi’s temperature variation of +2 to +48°C) giving automatic route setting to the timetable (ATS), bi-directional capability and 90-second headways

• ATP and ATO

• six sub-station supply points with a SCADA IP network

• six train maintenance depots

• an all-fibre cable network with SDH transmission

• Tetra track-to-train radio with 30 base station sites and radiating cable transmission, plus public GSM provision as well

• automated passenger information using both LED and LCD displays with multi-lingual messages and centralised digital announcements

• CCTV coverage monitored at local stations and the main control centre.

The convention visited the Metro HQ and, after a brief talk and video, the operations floor was seen from a viewing gallery. No photographs were allowed and no visit to a train depot, lineside equipment or training facility was programmed. There was a significant control system failure that day which may have impacted on the decision to keep our visit short. To many, this was a big disappointment.

India signal box
The signal box for Kalka's narrow gauge line

An up-country interlude

Formal visits completed, a splinter group took a trip on the broad gauge to Kalka and then the 2’6” gauge hill railway to Shimla which recently featured here in its own documentary series. This latter journey took over five hours for the 95km but was a delight. A leftover from the days of the Raj, the line features many reverse curves, a multitude of tunnels, classic signal boxes, lower quadrant signals and key token working, all of which seemed in good working order with proud and friendly staff. An unofficial visit to the operations control room on Shimla Station was easily achieved with the controller pleased to show how his antique train control equipment was used. Steam has given way to diesel but the ride experience is such that visitors come in their hundreds.

Shimla is a tourist destination and, to ease the chronic traffic congestion, the locals are pressing for a broad gauge link to be built. This would be expensive and unlikely ever to materialise. A more frequent service on the narrow gauge line would be possible and some speeding up of times could be achieved by cutting out the refreshment stops en route. However, this would detract from the line’s character.

What of the future?

India is a tiger economy with economic growth rates typically reaching 8%. This is concentrated in the business sector but it is very evident that services and infrastructure are not keeping pace. Much of the road system is appalling with long stretches of giant potholes. The main line railways could do much more to ease city congestion. A slick, frequent and fast commuter service should be easily possible. Getting the inter-city offerings up to a good standard is a goal they should set themselves. The metro systems being built in many cities prove that the vision and capability is there.

However, making a comparison with European standards is dangerous as India’s culture, way-of-life and priorities are totally different. Getting the country cleaned would, to western eyes, seem vitally important and one tour guide did suggest that this would happen in the next 20 years. One can only hope that he will be proved right.


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