Why the Third Rail?

[HTOLAS]

It is now clear that a faulty third rail (which supplies power to the MRT trains) was the main cause of the two major breakdowns last year and the current unavoidable daily breakdowns now. It has also emerged that the MRTC had declined a better (but presumably more costly) design of this third rail.

For me, this brings back a now forgotten debate: one between having power supplied to the train via a third rail and having it supplied via overhead cables. I recall that the powers-that-be were adamant that there were to be no overhead cables, for cosmetic and other reasons. The Presstapo then praised these same powers for their foresight and concern for our townscapes.

I remember at the time wondering why builders of train systems elsewhere did not have the same foresight. I looked through magazines, tourist pictures and other material for what other train systems looked like and remember that the vast majority of them had power supplied by overhanging cables. Even the Shinkansen (which I got to ride a little after our MRT started) was also electrified that way!



A few years later, there were talks between the Singapore government and KTM on the possibility of electrifying the trains between KL and Singapore. The deal was actually broken on the refusal by the Singapore government to allow overhanging electric cables to be used to power the trains when they were in Singapore. For KTM, it made no sense to equip their trains with two power supply systems just so they could travel between JB and Singapore.

I asked around and the surprising thing was that many engineers I spoke to thought that it was more sensible to use overhanging cables. I cannot confirm if they are right. Still, I wonder if the powers-that-be had chosen a 'better-looking' system over the more reliable one. I also begin to wonder where else looks might have triumphed over safety and functionality.

 

[Cestbon]

Pro and con of overhead line and 3rd rail near to the ground.

3rd rail on the ground more costly and easy to maintain.

Overhead line cheaper and more cost effective for long distance and high speed.

 

[Qantas]

Pro and con of overhead line and 3rd rail near to the ground.

3rd rail on the ground more costly and easy to maintain.

Overhead line cheaper and more cost effective for long distance and high speed.

Aiyah, u know our govt always want good-looking ones. Can I also add that overhead cables are safer cos there is less likelihood of someone being electricuted if they fall or step onto the rails?

 

[looneytan]

Aiyah, u know our govt always want good-looking ones.

This one I have to disagree, as many bros here can support me, look department does not play big part with our powers-that-be

 

[Cestbon]

For short distance like MRT/many city subway/metro is better to have 3rd rail. Because heavy usage,easy to maintain even though more costly. 3rd rail normally have 750V and below.

Almost all long distance and high speed using overhead rail. Doesnt need so many substation and normally overhead line power 12500V and above.

For SG 3rd rail is a good decision and choice.

 

[eatshitndie]

For short distance like MRT/many city subway/metro is better to have 3rd rail. Because heavy usage,easy to maintain even though more costly. 3rd rail normally have 750V and below.

Almost all long distance and high speed using overhead rail. Doesnt need so many substation and normally overhead line power 12500V and above.

For SG 3rd rail is a good decision and choice.

correct and good info. the bay area rapid transit (bart) also uses the 3rd rail for power. there has not been a major incident or breakdown involving the 3rd rail, although during nightly maintenance windows, 3rd rails have been known to lose alignment and slide off their elevated position. maintenance or at least a visual inspection of every 3rd rail is required every early morning (maintenance window of 1am to 5am). a separate maintenance train loaded with sensors and instrumentation is used. tracks also need to be inspected regularly, and if there is wear and tear they need to be replaced. bart replaces sections of tracks every day. it's a never ending job.