Sleepers, wood vs concrete vs slab.

Run_to_da_hills

I thought I would bring up this subject since a major track bed operation will be ongoing on on the Dart line between Dunlaoghaire and Glasthule over the holidays.

What are the benefits of each? I see timber still being used extensively on our rail networks particularly at points. I understand concrete sleepers can allow higher speeds.

What is the life span of each system?

It looks as if the Dart line between Dunlaoghaire and Sandycove has lasted 25 years under a poured slab system. Any idea what they will be replacing this with?

CIE

Run_to_da_hills wrote: »

I thought I would bring up this subject since a major track bed operation will be ongoing on on the Dart line between Dunlaoghaire and Glasthule over the holidays.

What are the benefits of each? I see timber still being used extensively on our rail networks particularly at points. I understand concrete sleepers can allow higher speeds.

What is the life span of each system?

It looks as if the Dart line between Dunlaoghaire and Sandycove has lasted 25 years under a poured slab system. Any idea what they will be replacing this with?

Slab track (i.e. no ballast) is supposed to be the best for safety at high speed, since there is no ballast to be knocked loose while running, which can damage the train as well as adjacent objects. (Since Germany has the habit of building their high-speed lines next to the Autobahn, this was certainly a consideration.) As for longevity, it seems that Dun Laoghaire through Sandycove and Glasthule (Glenageary??) has been way shorter than the average life span. Ballasted rail is supposed to be more vibration-absorbent (hence quieter) than unballasted. It's the most expensive in terms of capital costs, certainly. (The railway in question was ballasted up until the rebuild for DART.)

Concrete sleepers versus wood: I've heard figures quoted that the former is supposed to last an average of 50 years versus 30 for the latter (and elder technology). In addition, wood sleepers have to be treated with coal tar creosote to prevent them from rotting, and the environmental types are concerned with seepage into the groundwater and whatnot.

There are other alternative types of railway sleeper, such as steel (supposedly the newer designs are better at bearing loads than either concrete or wood, and even require less ballast, but the jury's still out) and even plastic/rubber composite sleepers made from recycled materials (especially tyres).

Run_to_da_hills

CIE wrote: »

There are other alternative types of railway sleeper, such as steel (supposedly the newer designs are better at bearing loads than either concrete or wood, and even require less ballast, but the jury's still out) and even plastic/rubber composite sleepers made from recycled materials (especially tyres).

I have seen steel being used extensivly in the Northern Territory of Australia, probably due to termites eating wooden sleepers.

kingshankly

you need to use different sleepers for different areas ie when making a crossover you need to use wooden sleepers as there is more give in them pus you can't put concrete sleepers on concrete bridges to help prevent vibrations

CIE

kingshankly wrote: »

you need to use different sleepers for different areas ie when making a crossover you need to use wooden sleepers as there is more give in them

I've seen plenty of concrete sleepers in crossovers. Might be cheaper to retain wood sleepers in the crossover area because of the need to custom-build the sleepers through the switches, if anything.

you can't put concrete sleepers on concrete bridges to help prevent vibrations

Plenty of instances of concrete sleepers on tracks on concrete bridges as well. Did you mean ballasted or unballasted?

Greenman

Run_to_da_hills wrote: »

I have seen steel being used extensivly in the Northern Territory of Australia, probably due to termites eating wooden sleepers.

On a recent trip to Morocco I saw steel sleepers used with the prepared lenghts of track, never saw them before anywhere else.:)

Run_to_da_hills

Greenman wrote: »

On a recent trip to Morocco I saw steel sleepers used with the prepared lenghts of track, never saw them before anywhere else.:)

Oncf would put CIE to shame, I travelled from Tangiers to Fez in the mid 80's the whole line was electrified back then. Being a former French colony all the rolling stock and locos come from France. A new high speed TGV line that will run down the east coast running down the east coast is due to open in 2012.

Judgement Day

The newly rebuilt Welsh Highland Railway between Caernarvon and Portmadoc makes extensive use of steel sleepers. I believe they are also widely used in parts of Africa. Redundant concrete sleepers are handy for use in coastal defence work but otherwise don't have much resale value unlike their wooden counterparts.



Rhyd-ddu Station on the Welsh Highland Railway.

A Dub in Glasgo

The newly opened Airdrie to Bathgate link in Scotland is all steel sleepers.

http://jonathanmcgurk.fotopic.net/p65652747.html

http://jonathanmcgurk.fotopic.net/p65652694.html

I think steel is now the preferred choice in the UK with wood for points

Run_to_da_hills

A Dub in Glasgo wrote: »

The newly opened Airdrie to Bathgate link in Scotland is all steel sleepers.

http://jonathanmcgurk.fotopic.net/p65652747.html

http://jonathanmcgurk.fotopic.net/p65652694.html

I think steel is now the preferred choice in the UK with wood for points

You would think that they would have them galvanized for Scottish weather.

Judgement Day

Bord na Mona use steel sleepers throughout their extensive system and I would have thought that the shape (of the undersides) of the sleepers are ideal for soft peat but I have always been mystified at their use with ballast. Obviously they work but I would have thought they would be a bastard for tamping be it manually or by machine.



Bord na Mona permanent (?) way.