Concrete v wooden v composite v metal sleepers - How are they selected?

[mrg9999]

Recently I noticed very old wooden sleepers being replaced with new wooden sleepers and wondered why they weren't using concrete or something else.
I asked the project manager and his unhelpful and suspicious answer was "It was requested by engineering, if you have any concerns ......."

I looked on Wikipedia that gives quite a lot of generic info

Railroad tie - Wikipedia

en.wikipedia.org

But still have questions

 

[edwin_m]

Wood and composite may be used where the ballast depth is limited, for example on certain viaducts.

 

[Trainman40083]

Steel sleepers were introduced on lightly used lines and at the end of their lifespan, they could be recycled. A concern on wooden sleepers (there were softwood and hardwood variant ls) is what do you do with them when they are "life expired"? At one time they could be sold for other uses, such as golf courses, but if I recall that was stopped cos of toilet effluent and weedkillers on them. So there is a cost of landfill. On heavily used lines you'd see concrete. Since COVID and other matters I recall the price has reportedly increased by about 80%. To make concrete you need raw materials, no doubt affected by ever increasing aggregate taxes ( which is why we are seeing more ballast recycling centres - old ballast sold off for hardcore etc, which gives developers a saving over using new aggregate. Price concerns will have seen the development of composite sleepers (I keep wanting to call them plastic). I don't know if they can be recycled.

 

[mrg9999]

Steel sleepers were introduced on lightly used lines and at the end of their lifespan, they could be recycled. A concern on wooden sleepers (there were softwood and hardwood variant ls) is what do you do with them when they are "life expired"? At one time they could be sold for other uses, such as golf courses, but if I recall that was stopped cos of toilet effluent and weedkillers on them. So there is a cost of landfill. On heavily used lines you'd see concrete. Since COVID and other matters I recall the price has reportedly increased by about 80%. To make concrete you need raw materials, no doubt affected by ever increasing aggregate taxes ( which is why we are seeing more ballast recycling centres - old ballast sold off for hardcore etc, which gives developers a saving over using new aggregate. Price concerns will have seen the development of composite sleepers (I keep wanting to call them plastic). I don't know if they can be recycled.

Thanks
Network rail used to give them to several local allotments but there were concerns about creosote, preservatives and poo after an environmental health person took some samples and recommended that they only be use where crops were not grown. My shed is build on a raft of old sleepers.

 

[Trainman40083]

Thanks
Network rail used to give them to several local allotments but there were concerns about creosote, preservatives and poo after an environmental health person took some samples and recommended that they only be use where crops were not grown. My shed is build on a raft of old sleepers.

Just think. Cost of product, cost of delivery, lifespan, cost of disposal. As an aside, I remember a heated discussion once about Douglas Fir. It was used as a longitudinal bridge timber. I used to manage the British Rail supply contract. Now Douglas Fir can come from a number of places. The BR contract specifically required North American/Canadian rather than UK/European. Colder temperatures (if I recall) meant it saw slower growth, giving a stronger timber giving a long lifespan. So, if the cost of product, installation and lifespan was taken into consideration, it was said to be more cost effective.

 

[alxndr]

As far as I know new timber sleepers aren't available any more, with composite being the replacement. I've certainly seen composite around a few more places recently, although it is quite hard to tell as they do look very much like brand new timber sleepers. The first time I saw them no one believed that I thought they were composite until I scratched at it with a knife. Anyone know if composite sleepers can be plugged and redrilled in the same way as timber sleepers can?

Steel sleepers can't be used where there is likely to be a high amount of salt (e.g. station platforms) due to corrosion issues.

 

[edwin_m]

FFU "synthetic wood" has started to be used on Network Rail fairly recently. https://sekisui-rail.com/ffu.html

Railroad sleepers made of FFU have been installed worldwide since 1980 and have therefore been in reliable use for over 40 years.

Switch systems and railway bridges are the preferred areas of application. But also the use as flat sleepers and track sleepers and for special constructions offers great possibilities to optimize the railway superstructure.
...
In addition to the high life expectancy, FFU synthetic wood can be recycled, which means that we are able to manufacture new products for the railroad sector but also for other areas of the construction industry.

I believe this can also be drilled. It has been featured in several articles in Rail Engineer magazine.

 

[D6130]

As far as I know new timber sleepers aren't available any more, with composite being the replacement. I've certainly seen composite around a few more places recently, although it is quite hard to tell as they do look very much like brand new timber sleepers. The first time I saw them no one believed that I thought they were composite until I scratched at it with a knife. Anyone know if composite sleepers can be plugged and redrilled in the same way as timber sleepers can?

Steel sleepers can't be used where there is likely to be a high amount of salt (e.g. station platforms) due to corrosion issues.

Steel sleepers were used extensively during the relaying of the Settle & Carlisle line between 1996 and 2001....and there are several stations - Settle, Kirkby Stephen and Appleby amongst them - where steel sleepers are used through the platforms.

 

[alxndr]

Steel sleepers were used extensively during the relaying of the Settle & Carlisle line between 1996 and 2001....and there are several stations - Settle, Kirkby Stephen and Appleby amongst them - where steel sleepers are used through the platforms.

Looking into it a bit more it's guidance rather than forbidden, but would make sense to give other options preference in salty environments.

 

[Ashley Hill]

As far as I know new timber sleepers aren't available any more, with composite being the replacement

The heritage line I volunteer on still obtains wooden sleepers for specific jobs. We’ve used hardwood Jarrah timber for pointwork. Very heavy and horrible to drill, plus a nasty smell when drilling.
Wasn’t there trials of composite sleepers around the country, how are they faring?

 

[Russel]

One of the Welsh narrow gauge lines has started using composite sleepers, I seem to recall reading somewhere.

 

[D6130]

The heritage line I volunteer on still obtains wooden sleepers for specific jobs. We’ve used hardwood Jarrah timber for pointwork. Very heavy and horrible to drill, plus a nasty smell when drilling.
Wasn’t there trials of composite sleepers around the country, how are they faring?

I've read somewhere - possibly on these forums - that composite sleepers are being used extensively in the current relaying operations on the Far North line.

 

[Bald Rick]

It’s generally pretty simple. Concrete for everything, unless specified otherwise.

Steel may be specifiedfor renewals on lines with low tonnage where the ballast is in reasonable condition. Whilst the sleepers themselves are more expensive, it makes the job overall much cheaper (no need to excavate, no ballast to move around, and one gang of labour with a couple of road railers can easily do 1000 metres of it in a weekend)

Timber will be used, for example where weight is a concern (eg on structures or culverts), there is less ballast depth, or where the track geometry requires some unusual / bespoke placement of rails (including check rails) that means drilling on site.

Composite can be used instead of timber.

As far as I know new timber sleepers aren't available any more, with composite being the replacement.

New timber sleepers are very definitely still available.

 

[Cambo_flyer]

Composite bearers are preferred for S&C as tropical hardwood timbers are no longer available due to sustainability concerns.

 

[Mcr Warrior]

What are the comparative weights of railway sleepers of similar dimensions (if indeed they are broadly all the same size)? Ones made of steel, concrete, wood (Douglas fir, oak, azobé, jarrah?), plastic composite? And is anything else occasionally used?

 

[Bald Rick]

What are the comparative weights of railway sleepers of similar dimensions (if indeed they are broadly all the same size)? Ones made of steel, concrete, wood (Douglas fir, oak, azobé, jarrah?), plastic composite? And is anything else occasionally used?

A standard G44 concrete sleeper weighs around 300kg.

Timber varies, but typically around 80kg (softwood), 120kg (hardwood)

Composite around 120kg too.

Steels are relatively light, can be as little as 40kg. Hence 2 gangers can lay them out by hand easily (and quickly).


I forgot to say earlier, concrete, timber and steel sleepers are all recycled. Old timber sleepers are chipped and the product can go off to biomass. Good Concretes are reused for sidings etc, and the rest are crushed, with the steel reinforcing cables recycled and the crushed concrete used in construction. Steels go for scrap as with other metal.

 

[Trainman40083]

Of course, the railway has also seen concrete troughing replaced by alternatives. A lot lighter, less susceptible to breakage, less injuries during installation, faster installation rate. More expensive as a product, but overall cost effective when installation taken into account. I bet a few of us have seen staff with heavy troughs on their shoulders.

 

[DarloRich]

I asked the project manager and his unhelpful and suspicious answer was "It was requested by engineering, if you have any concerns ......."

Why would it be "suspicious"?

New timber sleepers are very definitely still available.

Not creosote treated softwood ones and hardwoods are supposed to be from stock not "fresh"

("Stock" will relay from here to Jupiter and back apparently!)

PS - unsure about bearers.

 

[Trainman40083]

Why would it be "suspicious"?


Not creosote treated softwood ones and hardwoods are supposed to be from stock not "fresh"

("Stock" will relay from here to Jupiter and back apparently!)

PS - unsure about bearers.

Ah the smell of creosote.. Were they later they later given a different treatment. Tannal, something?

 

[CastlebarKeith]

Possible factors:
l was told that the price of timber has risen much faster than the alternatives recently
There are ecological and sustainability issues importing timber - it is hard work.
Even domestically, wooden garden decking costs a fortune now and the price gap between wooden and composite decking has narrowed.

 

[sharpener]

Ah the smell of creosote.. Were they later they later given a different treatment. Tannal, something?

Genuine Tanalising was good but I don't recall ever seeing it on raliway sleepers, it is a fairly bright green due to the copper arsenate on which it is based. The copper kills fungi and the arsenic kills any small forms of animal life. So it has been banned and current "treated" timber from garden centres and fencing contractors has a very short life in comparison IME.

 

[alxndr]

Of course, the railway has also seen concrete troughing replaced by alternatives. A lot lighter, less susceptible to breakage, less injuries during installation, faster installation rate. More expensive as a product, but overall cost effective when installation taken into account. I bet a few of us have seen staff with heavy troughs on their shoulders.

Although some polymer versions have been found to be rather less fire retardant than they claimed to be.

 

[Somewhere]

Steel sleepers can't be used where there is likely to be a high amount of salt (e.g. station platforms) due to corrosion issues.

Salt isn't used on station platforms.
And it isn't corrosion that's a concern - its activation of track circuits. That's why councils aren't supposed to spread salt on level crossings

 

[D6130]

Salt isn't used on station platforms.
And it isn't corrosion that's a concern - its activation of track circuits. That's why councils aren't supposed to spread salt on level crossings

Plenty of salt was used on the platforms at Hebden Bridge - and other Calder Valley stations - over the past couple of winters.

 

[Put Kettle On]

Salt isn't used on station platforms.
And it isn't corrosion that's a concern - its activation of track circuits. That's why councils aren't supposed to spread salt on level crossings

Must be at least 20 years ago, when the track was renewed at Saltcoats ( yes, the very track that appears in news reports of storm waves crashing over the sea wall there ) it was done with steel sleepers.

Doesn’t appear to be greatly afflicted by track circuit issues.

There are numerous other locations where steel sleepers have been used in close proximity to sea front areas.

 

[alxndr]

Salt isn't used on station platforms.
And it isn't corrosion that's a concern - its activation of track circuits. That's why councils aren't supposed to spread salt on level crossings

The guidance I’ve read from 2024 states: “Cat 3 to 6, not in platforms, 3rd rail areas, jointed track, or locations where salt corrosion is likely, not on curves less than 500m. Strengthening/guard rail designs also available. Refer to TRK2102 for all restrictions of use”

Not my area of expertise but it seems logical to me.

If it’s not salt they use on platforms it’s something very similar. It certainly affects track circuits (even if not steel sleepered).

 

[Ploughman]

It’s generally pretty simple. Concrete for everything, unless specified otherwise.

Steel may be specifiedfor renewals on lines with low tonnage where the ballast is in reasonable condition. Whilst the sleepers themselves are more expensive, it makes the job overall much cheaper (no need to excavate, no ballast to move around, and one gang of labour with a couple of road railers can easily do 1000 metres of it in a weekend)

Timber will be used, for example where weight is a concern (eg on structures or culverts), there is less ballast depth, or where the track geometry requires some unusual / bespoke placement of rails (including check rails) that means drilling on site.

Composite can be used instead of timber.



New timber sleepers are very definitely still available.

Back in about 2000 In a normal 23.00-Sat 06.00 mon weekend possession we uplifted BH track panels between Broomfleet and Gilberdyke and relaid Steel Sleepers over 4400m

 

[AndrewE]

Must be at least 20 years ago, when the track was renewed at Saltcoats ( yes, the very track that appears in news reports of storm waves crashing over the sea wall there ) it was done with steel sleepers.

Doesn’t appear to be greatly afflicted by track circuit issues.

There are numerous other locations where steel sleepers have been used in close proximity to sea front areas.

Is Saltcoats track circuited? I remember the Merseyrail loop was plagued by track circuit failures when the (brackish) water table rose and flooded the tunnels, shorting out the circuits. After a 6-week (I think) closure it reopened with one of the early installations of axle-counters.

 

[alxndr]

Is Saltcoats track circuited? I remember the Merseyrail loop was plagued by track circuit failures when the (brackish) water table rose and flooded the tunnels, shorting out the circuits. After a 6-week (I think) closure it reopened with one of the early installations of axle-counters.

Saltcoats was replaced with axle counters in the late 90s

 

[Bald Rick]

Back in about 2000 In a normal 23.00-Sat 06.00 mon weekend possession we uplifted BH track panels between Broomfleet and Gilberdyke and relaid Steel Sleepers over 4400m

Bet you had more than one gang though!