1991 WR Short rails in four-foot

[arn3696]

Hi all

Just watching the NSE Cabride video filmed in early 1991 on the Up Relief from Reading to Paddington - really takes me back to my childhood! My question is whether anyone could shed any light on the purpose of what appear to be short sections of rail attached to the sleepers in the four-foot? I have done a quick search but as I have no idea what they are for I'm not having much luck finding answers.
They appear quite frequently - see attached pics from Portobello Junction near Westbourne Park - first on adjacent DR to the right of shot and second on UR ahead of the train.



TIA

Chris

 

[themiller]

To keep the running rails aligned at an expansion joint at the end of a continuously welded rail section. You can just see the mitre on the running rails.

 

[arn3696]

To keep the running rails aligned at an expansion joint at the end of a continuously welded rail section. You can just see the mitre on the running rails.

Great! Thanks for that. Didn't even cross my mind.

Cheers

 

[Elecman]

Expansion joint alignment

 

[edwin_m]

Only needed if there is some part of the track that can't withstand the expansion forces in continuously welded rail - in this case probably the switches and crossings beyond. Modern S&C can withstand those forces so doesn't need expansion joints.

 

[LSWR Cavalier]

I think CWR still tries to expand and contract. How is this stopped? Can something give, or are the tapered expansion joints enough for +30° to - 30°?

 

[furnessvale]

I think CWR still tries to expand and contract. How is this stopped? Can something give, or are the tapered expansion joints enough for +30° to - 30°?

Expansion joints are only required at the ends of a CWR section, which can be miles long. Only the last 200m or so can move with heat. Throughout the main length, the track is held in place by the strength of the fastenings and ballast so it cannot move, and all the potential expansion/contraction is kept within the rail as internal stresses. To assist with this, rails are "destressed" by stretching them when laid to the length they would be at 80 degreesF. It used to be 70 when I worked on the railway, it went up to 80 and may even be more nowadays.

At the ends of a CWR section, the rails can move because the non CWR track the CWR is attached to, has insufficient strength to resist the forces involved, hence expansion joints must be fitted for this movement.