Luas again: Third rail on Taney Bridge

mackerski

Folks,

I went for a walk over the Taney Bridge over the weekend, and was surprised to see a third rail in each direction, about 15-20cm inside the main inner rail. This third rail is old-style, joined with fishplates and not clamped down very securely. It runs for the length of the bridge. As you would imagine, its surface has a thin coating of rust that shows that nothing is running over it.

Can anybody explain the purpose of this?

Dermot

parsi

Is it some class of a check rail (prevent total derailment) ?

John R

Are you supposed to be walking on that bridge?:D

Normally the only place an addition rail is seen is on tight curves but that bridge is straight isn't it?
Perhaps it is because of the movement of the bridge, cable stay bridges do tend to move in the wind.

mackerski

Are you supposed to be walking on that bridge?

Funny you should ask - the quick answer is "yes", on one side of the deck there's a black strip with a pictogram of a pedestrian on it. There's also a pathway leading up to the non-station end of the bridge. The walkway provides access to the station and also a way of avoiding traffic on the junction below.

The funny thing is that in those parts of the Luas system where you're _not_ supposed to walk, they've chosen a novel sign to illustrate this. There's a standard international sign to indicate a prohibition on pedestrians. It's round with a red border, a white background and a pictogram of a pedestrian. The Luas, on the other hand, uses the exact same sign but with a red stroke through it. You've got to love this country...

BrianD

You see these extra rails on a lot or railway bridges as well.

Lady

You can see the third rail here: http://busesinireland.bravepages.com/files/dundrum_bridge.JPG


Id say John R is right about the bridge movement.

Mark B OBO Goddess.

Andrew Duffy

Our warning signs are not the same as the ones used in Europe; they're the same as the North American ones for the most part. Besides, considering stupidity of an element of the Irish public, the clearer a sign is the better.

mackerski

Our warning signs are not the same as the ones used in Europe

Except, of course, in those cases where they are the same. Most of the round red-bordered signs that we use are international standard - the speed limits, the blank-faced one that means no vehicles. For the no overtaking one, they've used the same silly approach of taking the recognised international sign and negating it.

American signs are not big on pictograms or even convention. When they want a speed limit, they put up a big, square sign with "Speed Limit" and a number on it. If they want to prohibit pedestrians, one feels the sign would say "pedestrians prohibited". Europe, though, tends to favour pictograms, presumably because they work well in a situation where a lot of people travel and may not speak the local language. This makes the butchering of well-known signs particularly daft...

Dermot

MogwaiFearSatan

it looks like a power rail. it could be a failsafe incase the overheads are damaged that'll get a tram off the bridge.

mackerski

'Tisn't a power rail - though that would be one way to discourage wanton vandalism on the line...

John R

Originally posted by MogwaiFearSatan
it looks like a power rail. it could be a failsafe incase the overheads are damaged that'll get a tram off the bridge.

It is most certainly not a power rail. The LUAS system is overhead power only. It is no longer allowed to use live rails in new overground lines.

It is too far away from the running lines to be a check rail as are sometimes used on tight curves.

jd

Originally posted by John R
It is most certainly not a power rail. The LUAS system is overhead power only. It is no longer allowed to use live rails in new overground lines.

It is too far away from the running lines to be a check rail as are sometimes used on tight curves.

Maybe they are future proofing and putting in the third rail for a metro!!

(I'm not serious)

Space Cube 40

Any future metro in Ireland shall be run by OHLE and not 3rd rail. This has been stipulated by the Rail Authority and shall not change.

My opinion is still with the fact that it is on a bridge and thus could be subject to swaying.

Mark OBO "SC40"

Crossley

Our warning signs are not the same as the ones used in Europe

And it's long overdue that they be brought into line. How we ended up with the current mish-mash is beyond me. I suppose it's too much to hope that Seamus Brennan's much announced review of speed limits and the associated changing of limit signage will do anything in this regard ?

monument

Originally posted by mackerski
Can anybody explain the purpose of this?

They were having a bit of a problem putting down the concrete sleepers for the LUAS track – so they put a piece of old track there to hold the sleepers down until the superglue sets in. :dunno:

Victor

Originally posted by monument
They were having a bit of a problem putting down the concrete sleepers for the LUAS track – so they put a piece of old track there to hold the sleepers down until the superglue sets in. :dunno:

No, no sleepers in this case (they did do something similar somewhere on the dart alright, with sleepers cast into concrete).

monument

Well sleeper looking thinks… err… superglue… could resist a cheep-shot dig at the mess that is LUAS.

enterprise

A quite old post:

The additional rail in between the running rails is a "check rail". If a tram de-railed while crossing the bridge this check rail would contain the tram to the centre of the bridge, therefore stopping it from crashing down onto the street below.

Check Rails can be found on tight curves and when crossing major bridges.

A Dub in Glasgo

I agree with enterprise here.

They can buggers to deal with if you need to install equipment between the rails. We had quite a problem installing TPWS on the Forth Rail Bridge which has quite a lot of check rail.

enterprise

A Dub in Glasgo wrote:

I agree with enterprise here.

They can buggers to deal with if you need to install equipment between the rails. We had quite a problem installing TPWS on the Forth Rail Bridge which has quite a lot of check rail.

I imagine that was fun!