What's the story with the Bray-Greystones tracks?

That username is already in use.

Why are there two inner rails?







And why does this section have six rails?

Jamie2k9

They are there to stop a complete derailment and damage to whatever is beside the line. If rocks fell and the train was going fast it would be in the sea if it derailed and those centre lines were not there. They will catch the wheels from one side of the train and stop a full derailment.

They have them under certain bridges, so the bridge isn't damaged if a derailment was to happen.

flyingsnail

As above they are to contain any derailment and seemed to work nicely with the recent DART derailment.



http://www.independent.ie/irish-news/irish-rail-criticise-reprehensible-derailment-by-vandals-30418190.html

Captain Chaos

I though the check rails that do that are placed just inside the running rails themselves like the ones on the loop line bridge from Connolly to Pearse. I don't see the point of them being in the middle of the sleepers as the train can move off the rails much further before it's stopped unlike standard check rails.

Jamie2k9

Captain Chaos wrote: »

I though the check rails that do that are placed just inside the running rails themselves like the ones on the loop line bridge from Connolly to Pearse. I don't see the point of them being in the middle of the sleepers as the train can move off the rails much further before it's stopped unlike standard check rails.

Don't really know where you are talking about (don't use DART much) but where you normally check rails is before and after points.

Can only think they are in the middle to ensure a full derailment doesn't happen as it probably really depends what the train hits and how much movement is caused as if its substantial it will likely jump the check rail if it was beside the edge.

It just seems like they want ehatever falls to be raised to wheels level and the aim is for the train to push it forward instead of rolling over it completly which could lift the train. Its likely that whatever rock falls it will rest on at least one of the 4 rail heads with the positioning on the line which is unlikely if they are all at the edge.

corktina

could they not be new rails in position to fit shortly?

Captain Chaos

corktina wrote: »

could they not be new rails in position to fit shortly?

I was thinking that at first as that is what they do look like but on closer viewing you can see that they are clamped to every sleeper.

Here is a pic for the tracks between Tara and Pearse stations showing the check rails the whole way.
http://www.thewandererphotos.com/2014Photos/October-2014/i-V85BvZf

https://www.flickr.com/photos/flyingsnail/3896684461/

Jamie2k9

Here is a pic for the tracks between Tara and Pearse stations showing the check rails the whole way.
http://www.thewandererphotos.com/201...2014/i-V85BvZf

From doing a Google search they are there to ensure primary no damage is caused to a structure (bridge in this case)

Railway trackage has guard rails (aka check rails) for at least 2 general reasons: first to guide wheels through possible catch points on turnouts or diamonds. Similarly, guard rails may be installed inside the innermost running rails on very sharp curves. The other most common usage is to prevent damage to other structures, especially bridges, in a derailment.

On sharp curves, guard rails may be placed inside the inner rail, where they engage the back of the flange of the wheel on that side

Isn't much about them being placed in the center but could speed on sections of track be a factor.

Captain Chaos

That's why I was wondering why the Greystones check rails are installed the way they are. They make no sense to me for helping with derailments and look more like to help keep the sleepers from spreading or the track from twisting or flexing too much with rock movements.

That username is already in use.

Captain Chaos wrote: »

They make no sense to me for helping with derailments and look more like to help keep the sleepers from spreading or the track from twisting or flexing too much with rock movements.

How wouldn't they help to prevent derailments? Bogie hops off the main tracks and gets caught by the inner tracks, no?

They have the exact same configuration on the southbound track exiting the Vico Road tunnel, but not northbound. Seems to me like an extra safety measure to stop the DART flying off the cliff.

Captain Chaos

It's just if you compare them to the ones I posted they don't seem to be as effective as the ones I linked to, as they make it virtually impossible to de rail at all. Not so with the Greystones rails as the train can move a few feet laterally before its caught. Just questioning their design for their task if it is their task and not something else.

Jamie2k9

Captain Chaos wrote: »

It's just if you compare them to the ones I posted they don't seem to be as effective as the ones I linked to, as they make it virtually impossible to de rail at all. Not so with the Greystones rails as the train can move a few feet laterally before its caught. Just questioning their design for their task if it is their task and not something else.

Wouldn't say they are not effect as they did stop a full derailment earlier this year. Maybe its just more effective for a large obstruction.

On the quad track at Park West where the M50 bridge both fast lines have both in the center to.

Judgement Day

Interesting footage of a derailment on Bray/Greystones section in 1923.

https://www.youtube.com/watch?v=OCc8op7EcjI

Should this thread be in the Train & Rail Systems sub-forum?