Why does the track have double lining?

Chunghong2004 SG

I wondered in the MRT tracks, why are there another similar track within the track itself (usually black in colour if new)?

shinkansen SG

To prevent derailing and fall off the viaduct. Please correct me if I'm wrong. Thanks.

SBS9231S SG

it does not prevent derailment but prevents the train from falling of the viaduct

skystopper SG

@ SBS9231S

Doesn't falling off the viaduct consider as a derailment?

I've always thought that those are just spare ones that can be use to replace the worn-out rail, so that it won't be that troublesome to get new ones from the depot to replace them.

Ice kosong SG

hardly take mrt so didnt observe but could it be for work / service train tat uses different track gauge?

Call4ljw SG

The wheels actually lay on all tracks.

One wheel on two tracks.

They previously showed the underneath of the train during a channel 8 show.

willis_chong SG

The wheels actually lay on all tracks.

One wheel on two tracks.

They previously showed the underneath of the train during a channel 8 show.

One wheel cannot go on two tracks...

The inner rails cannot support running of trains throughout the whole stretch as they are absent on at-grade and underground tracks. If trains were to run on the inner rails, their bogies will be severely damaged as the inner rails converge before they disappear, and the wheels of trains running on inner rails will get damaged at crossovers as rails will cut in.

Therefore the only use of it is to prevent trains from falling off viaducts or onto roads. Trains can still derail, but the inner rails will trap the train's wheels to prevent the train from falling out.

skystopper SG

The wheels actually lay on all tracks.

One wheel on two tracks.

They previously showed the underneath of the train during a channel 8 show.

Also, how is the train suppose to change tracks then? Trains running underground only have a single track.

I was wondering if Alstom Metropolis C830 can also run on NSL and EWL, since it is on 3rd rail as well.

edit: Is the engine on the first and last train carriage?

Call4ljw SG

One wheel cannot go on two tracks...

I remember see the wheel on both tracks. I dont remember what show that is.

d143b2 SG

Also, how is the train suppose to change tracks then? Trains running underground only have a single track.

I was wondering if Alstom Metropolis C830 can also run on NSL and EWL, since it is on 3rd rail as well.

edit: Is the engine on the first and last train carriage?

the C830s cant run on NSEWL

different system

and engine in middle carriages

aka blue and green carriages

Call4ljw SG

Also, how is the train suppose to change tracks then? Trains running underground only have a single track.

I was wondering if Alstom Metropolis C830 can also run on NSL and EWL, since it is on 3rd rail as well.

edit: Is the engine on the first and last train carriage?

Doesnt matter, you wouldn't want them running on NSL EWL, your waiting times will be longer than 6min if they do. =)

d143b2 SG

they run on RM

so no more than 15km/h (or so)

willis_chong SG

I remember see the wheel on both tracks. I dont remember what show that is.

You must've seen wrongly. Go AMK and observe. The wheels only touch the rails on the far ends. This also explains why the outer rails are silvery and the inner ones aren't. They are silvery due to friction of wheels running over them over time. The inner rails don't get run on, so they remain dull.

shinkansen SG

Doesnt matter, you wouldn't want them running on NSL EWL, your waiting times will be longer than 6min if they do. =)

All our MRT train run on a standard rail gauge.

shinkansen SG

the C830s cant run on NSEWL

different system

and engine in middle carriages

aka blue and green carriages

Our MRT doesn't have any engine, only have electric motor. There is 4x motorise carriages + 2 trailing carriages at both end. Our NSL and EWL train use 750V DC supply from the 3rd rail. That 3rd rail supply is from a stepdown transformer from a 6.6kV substation.

Please correct me If I'm wrong. I work in a power station therefore I know how the power grid work.

Call4ljw SG

Please correct me If I'm wrong. I work in a power station therefore I know how the power grid work.

How do you know the substation is 6.6kV?

Sorry to disappoint you, but no need to work in a power station to know this stuff.(no offense)

shinkansen SG

Yes Of cause. I may not work in the MRT / station but I can tell u that they are critical to our MRT system! Previously some contractor damage a underground High Voltage cable and cause a power distruption to some part of the MRT line. As a result the contractor was given a fined by the EMA (Energy Market Authority) for damaging the cable.

joeyfjj SG

The outer rails are the the running rails, the inner rails the guard rails. Trains run on the running rail. The guard rail is something like kerbs on the road side, stops the train from falling off, but normally does not serve a purpose. At crossovers, the guard rails ends. Trains run on third rail, 750 volts DC if I'm not mistaken. Motors are mounted on the train bogies of the 4 carraiges in the middle. The outer 2 carraiges are "driving trailers": They do not have motors. C830s running on the Circle Line uses a different signalling system, thus, they can not pratically run the NS/EW Lines. There are other factors like differing loading gauge.

theWEIRDme SG

just to ask about trains too, in circle and NE lines, when u head to the front or rear carriage, you see that there is ‘dangling’ cable lines on the ceiling outside the train. does the train actually hook onto these ‘dangling’ cables for power?

shinkansen SG

That one is the overhead cable, It does not hook but it just make contact to it. This is the one and only line which use overhead cable.