Jump to content
Attention: In order to reply to messages, create topics, have access to other features of the community you must sign up for an account.

Where is the power commnig from?


553 Bridgeton

Recommended Posts

I've always wondered about this kind of thing when I see sections of track that seem to not have a third rail. How many cars need to be connected to the rail to power the whole train? Is the voltage from one car able to power the others connected to it?

Link to comment
Share on other sites

I've always wondered about this kind of thing when I see sections of track that seem to not have a third rail. How many cars need to be connected to the rail to power the whole train? Is the voltage from one car able to power the others connected to it?

 

One shoe (the yellow thing sticking out on the side) is needed for all of them to have 600 volts

Link to comment
Share on other sites

Wirelessly posted via (Mozilla/5.0 (Danger hiptop 4.6; U; rv:1.7.12) Gecko/20050920)

 

Forget about the 160, the Slant right next to it is WAYYYYYYY more awesome! :P

 

Yeah but I think its missing something important...I think its a driver :P

Link to comment
Share on other sites

There are a bunch of questions raised in this thread I will try to answer all of them.

 

First, for a subway CAR to have full power, one of its four shoes must be on the third rail.

 

For a subway TRAIN, the answer is more complicated. When a car loses third rail it loses its traction motors and it loses its HVAC. Critical subsystems continue to run normally - including lights, door control, etc. This is not an issue because third rail gaps are small and spaced apart, so that a whole train won't gap out, and enough cars are on third rail at any given time so that there is enough power in the train collectively so that the motors are able to move the entire consist even if one or two cars have to drop out where the third rail gap is. However exactly how many shoes need to be on the third rail depends on track conditions. More will need to be on the third rail for instance, going uphill around a curve, than on flat ground or downgrade.

 

In the case of loss of third rail power, a train can keep those critical subsystems powered for a while. I don't remember how long for an older (SMEE) train, however for a new tech, the APU can keep them running for about an hour.

 

Second, there are a couple things that can be used to power cars in shops where third rail is not accessible. Most commonly, the undercar knife switch is placed in the "shop" position and a jumper is inserted into the knife switch. The jumpers are everywhere in the shops and hang down from above. This provides 600 to everything in the car EXCEPT the traction motors and third rail shoes because it is not desired for the train to be able to take power or have "hot" shoes at this time as inspection and maintenance is going on and it's dangerous for the train to be able to move or have 600 exposed. That is what you see in the photo above when the cars are in the shop.

 

When the cars need to be pulled out of the shop, commonly another train will couple up to it from outside the barn (where there is third rail) and pull it out. However, sometimes "the bug" will be used. The bug is an equally high voltage jumper that goes directly onto the contact shoe after the knife switch has been placed in the "normal" position and the box closed which provides power to that car the same as third rail would. One or more shop workers hold the bug in place and the train takes power - slowly - out of the barn until it is back on third rail, at which point the bugs are removed and stored away again.

Link to comment
Share on other sites

However, sometimes "the bug" will be used. The bug is an equally high voltage jumper that goes directly onto the contact shoe after the knife switch has been placed in the "normal" position and the box closed which provides power to that car the same as third rail would. One or more shop workers hold the bug in place and the train takes power - slowly - out of the barn until it is back on third rail, at which point the bugs are removed and stored away again.

 

That was the procedure described to us during the tour of the Hillside Maintenance Facility after someone asked.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.


×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.