Technology Update

Introducing the Third Rail system in India

Authored by:

Narendra Shah M a n a g i n g Ed i tor Metro Rai l N ews

As the Kanpur Metro has given a c Wilson for electrification for Third going to be first of its kind in India, ontract to S Rail system the scenario terling & which is of Metro operations is going to change rapidly in the coming years. Uttar Pradesh Metro Rail Corporation (UPMRC) which is the nodal agency forthe development ofKanpur Metro Rail Project is going to experiment with the technologyofthe third rail system which is very new to India. As we proceed further, we need to know something about the third rail system and its working mechanism. Third-rail system is a means ofproviding electric traction powerto trains, and the system uses an additional rail which is known as “conductor rail” for its work. The conductor rail is placed on the sleeperends mostly located outside ofthe running rails. However, a central conductorrail is also used in some cases.

In the existing system of electric traction for providing power to trains, the electrification is generally done a few feet above the upper body of metro or train coaches. The Third Rail system runs with the rails itself, making it easy to use matter for the trains. However, it is not free from cons as it maycreate trouble as well ifit rains orthere is a flood-like situation.

The Third rail system may cause trouble through electric shock because it carries a very high voltage near the ground. The electrified rail also can create a loss of lives, especially when someone falls on the tracks accidentally. As stated above, the flood like situations also may make it a dangerous thing. The overhead system on the other side may be troublesome when there is s higher wind flow or something of the same kind. Many Countries are using this system as of now. Let us have a few examples here.

France The newtramway in Bordeaux (France) uses a novel system with a third rail in the centre ofthe track. The third rail is separated into 10 m (32 ft 10 in) long conducting and 3 m (9 ft 10 in) long isolation segments. Each conducting segment is attached to an electronic circuit which will make the segment live once it lies fully beneath the tram (activated byacoded signal sent bythe train) and switch it offbefore it becomes exposed again. Netherlands To mitigate investment costs, the Rotterdam Metro, basically a third-rail-powered system, has been given some outlying branches built on the surface as light rail (called Sneltram in Dutch), with numerous level crossings protected with barriers and traffic lights. These branches have overhead wires. Similarly, in Amsterdam one “Sneltram” route goes on Metro tracks and passes to surface alignment in the suburbs, which it shares with standard trams. In most recent developments, the RandstadRail project also requires Rotterdam Metro trains to run underwires on theirwayalong the formermainline railwayto The Hague. The light rail vehicles on this line are capable of using both 600 VDC and 750 VDC.

London The North London Line changes its power supply once between Richmond and Stratford at Acton Central. The route was originally the third rail throughout but several technical electrical earthing problems, plus part ofthe route also being covered already by overhead electric wires provided for electrical-hauled freight and Regional. Mixed services are used in manyEuropean countries to make the system more efficient and safe. If one pedestrian walks on these rails, it is for sure that he/she will be no more after getting such heavyelectric shock. Any technology has its own merits and demerits. Nothing in this world is perfect and safe remains in trend when it comes to the Third Rail system. It is the work of the authorities to ensure that proper planning like that ofNetherlands is made so that chances ofcasualties may be reduced. Its use on a vast scale will surely help to make metros and trains operate even during the heavy winds or similar conditions. The future indeed depends on the way of execution, and ifthe plans are properly executed, it is for sure that the Third Rail system will prove to be a game-changer.