Engineering question about electric trains
Posted by: Deane F on 27 November 2006
I am on holiday in Melbourne at the moment and have been using the trains most days. They are electric trains powered from an overhead wire - with a pantograph providing the contact. I started to wonder how the contact shoe and overhead wire lasted any amount of time with the continual friction. I've looked it up on the net (which is how I found that the assembly on top of the train is a pantograph) and understand that the overhead wire zigzags slightly down the track to avoid a single point of contact on the shoe.
But the train is travelling at 80kmh most of the time. I just don't see how the wire doesn't wear through the shoe within 10 or twenty kilometres - especially as the pantograph is applying what must be a reasonable amount of pressure to the contact.
Can anybody clear this up for me?
But the train is travelling at 80kmh most of the time. I just don't see how the wire doesn't wear through the shoe within 10 or twenty kilometres - especially as the pantograph is applying what must be a reasonable amount of pressure to the contact.
Can anybody clear this up for me?
So I'm guessing the shoes at the top of the pantographs are copper or carbon or other soft(er) material that is a good conductor.......that way they can be easily changed out as opposed to the overhead cables!
But I'm no electrical engineer.......I just generate, distribute, isolate, and generally try and avoid contact with the stuff as much as possible.....
A good question though Deane, and I have often thought the same while riding the trains over in The Netherlands (gorgeous other half's work HQ is based over there), I was interested in the way the cables were suspended too.....with what looks like clips that only grip the sides of the cables alternating from side to side as you run down the length, again either for balance or to reduce ware and tear.....
Clever stuff indeed.
Cheers,
Ali
But I'm no electrical engineer.......I just generate, distribute, isolate, and generally try and avoid contact with the stuff as much as possible.....
A good question though Deane, and I have often thought the same while riding the trains over in The Netherlands (gorgeous other half's work HQ is based over there), I was interested in the way the cables were suspended too.....with what looks like clips that only grip the sides of the cables alternating from side to side as you run down the length, again either for balance or to reduce ware and tear.....
Clever stuff indeed.
Cheers,
Ali