Split sleeper track?

[dgrafix]

Just curious, i understand timber track, concrete sleeper track and block/spike raised track.. but what about split sleeper track like is found in Europe and Asia on HST lines? Is the center bar just deeper under the ballast because of the stresses or is it to help with things like superinclines or saving concrete? I would have thought it would be more stable with a "locked" gauge.... :/
What is this track even called?:

 

[santafewillie]

Danny - Sorry that I cannot answer your question, but nice picture. Did you take it?

 

[Smudge617]

Just curious, i understand timber track, concrete sleeper track and block/spike raised track.. but what about split sleeper track like is found in Europe and Asia on HST lines? Is the center bar just deeper under the ballast because of the stresses or is it to help with things like superinclines or saving concrete? I would have thought it would be more stable with a "locked" gauge.... :/
What is this track even called?:
View attachment 172166

I can see why you think it's "split" track, it isn't, it's one concrete sleeper, it's the way it's shaped and ballasted.

The center of the sleeper is concave in the middle, and is also pre-stressed, this gives a stronger sleeper to hold the rail in place, as railway tracks are not fixed, but are simply laid down, this newer style sleeper gives better overall performance and will (supposedly) last longer.

The reason concrete sleepers are used worldwide in preference to wooden ones, is, concrete has proved to have better sound and vibration dampening properties. That's why rail tracks have always been ballasted, not only to have a firmer base for the rail, but also to reduce vibration, which could cause the spikes or fishplates to work loose on wooden sleeper tracks.

 

[dgrafix]

I can see why you think it's "split" track, it isn't, it's one concrete sleeper, it's the way it's shaped and ballasted.

The center of the sleeper is concave in the middle, and is also pre-stressed, this gives a stronger sleeper to hold the rail in place, as railway tracks are not fixed, but are simply laid down, this newer style sleeper gives better overall performance and will (supposedly) last longer.

The reason concrete sleepers are used worldwide in preference to wooden ones, is, concrete has proved to have better sound and vibration dampening properties. That's why rail tracks have always been ballasted, not only to have a firmer base for the rail, but also to reduce vibration, which could cause the spikes or fishplates to work loose on wooden sleeper tracks.

Thanks for the reply, i know most concrete sleepers are concave, but they do not usually go -below- the balast. These are so close together i was trying to figure out if most of them are separate with every so many having some kind of retaining system, either a complete deep sleeper or some other way of holding it together.

 

[dgrafix]

Aha mystery solved!!
Apparently this is a new standard of sleeper called "U41 bi-bloc sleepers". They are lighter, cheaper, easier to integrity test & replace/repair. Also apparently better for the environment (as it uses less concrete which is not the most clean product)

"Figure 3: Another sleeper design consists of two concrete blocks joined by a steel bar. It is 30% lighter than a regular concrete sleeper, allowing it to be moved manually. It is popular in France (where it is called Stedef) and for some lighter track forms like those used for tramway systems. Here is an example in Manchester, awaiting a second layer of ballast to take it up to sleeper level."

Danny - Sorry that I cannot answer your question, but nice picture. Did you take it?

No, just a "google public domain" image.

 

[dgrafix]

It seems Pico are making this

Peco SL106F Gauge H0 Flex track concrete sleeper bi-block, code 75; 914mm modellbahnshop-lippe.com

modellbahnshop-lippe.com - Online Shop for model trains and accessories - Märklin • PIKO • Roco • Trix • Fleischmann • ✓ Great offers ✓ Great selection ✓ Short delivery time ✓ Top service

www.modellbahnshop-lippe.com

Wonder if kato will, or maybe I can get jiggy with a craft knife (but nah... that stuffs expensive, and so is my time!!)
Maybe sometime in the future if and when i can expand what i have.

PS this is the version you often see in Asia, where the whole roadbed is in concrete block sections with no loose ballast. KATO do an alternate version of this for all their double track and the viaduct units (but the French and Germans had me confused as it looks similar, but with aggregate ballast lol):

 

[dave1905]

There are all sorts of concrete tie designs. Many have a thinner cross section in the middle, which gives the "two tie" appearance when ballasted. Wood ties are not out and in some places are preferred to concrete.

For example, on primarily freight lines where derailments are more likely, wood ties are in some ways superior. You can drag a derailed car for miles across wood ties and the ties will still be structurally sound. If a car derails on concrete ties the ties that are marked have to be replaced. In some conditions the concrete ties react with the acidity in the soil and degrade more quickly.

 

[dgrafix]

There are all sorts of concrete tie designs. Many have a thinner cross section in the middle, which gives the "two tie" appearance when ballasted. Wood ties are not out and in some places are preferred to concrete.

For example, on primarily freight lines where derailments are more likely, wood ties are in some ways superior. You can drag a derailed car for miles across wood ties and the ties will still be structurally sound. If a car derails on concrete ties the ties that are marked have to be replaced. In some conditions the concrete ties react with the acidity in the soil and degrade more quickly.

Makes total sense

 

[J.Albert]

Almost anyplace that moisture can collect underneath concrete ties, they'll start to crumble into pieces from the bottom up. You can see this as you're going down the line from the cab -- the wet spots will be covered "in white", which is dust from the decaying ties underneath.

It got so bad on Amtrak that they had to take the concrete ties OUT of the East Haven tunnels, and put wood ties back in...

 

[rgeiter]

Early American and maybe British railroads used granite, or some other type of rock blocks, for railroad ties before wood.

 

[dgrafix]

The reason I am asking is mainly curiosity. The other reason is because my layout is a kind of 2 sided world featuring a country scape at one end with wooden ties and the other end will be a modern high speed cityscape at the other... One end will mainly function as a turn around for the other.
I was curious about these ties though, and now I know so thanks for the replies . It would be nice to see an HST at 200MPH+ running on wood, but have not yet found a good example. Would be nice to validate the parts of my layout when running at that scale speed to be able to say yes that is possible.

 

[Smudge617]

The reason I am asking is mainly curiosity. The other reason is because my layout is a kind of 2 sided world featuring a country scape at one end with wooden ties and the other end will be a modern high speed cityscape at the other... One end will mainly function as a turn around for the other.
I was curious about these ties though, and now I know so thanks for the replies . It would be nice to see an HST at 200MPH+ running on wood, but have not yet found a good example. Would be nice to validate the parts of my layout when running at that scale speed to be able to say yes that is possible.

I'm sure there are, but unlikely to be at 200mph as the force exerted on the track would be more than a 100 ton locomotive travelling at 100mph, which is around the maximum a wooden sleeper could be expected to repeatedly withstand.

 

[dgrafix]

I'm sure there are, but unlikely to be at 200mph as the force exerted on the track would be more than a 100 ton locomotive travelling at 100mph, which is around the maximum a wooden sleeper could be expected to repeatedly withstand.

That's what i thought, the stress on the trackbed at such speeds must be very incremental the faster you go (hockeystick graph exponential style) I have only ever found concrete on very modern railways like HS1/Eurostar, HS2 (as far as we know), the "Shinkansen" (japan, china, korea) and the high speed links in Europe all seem to use concrete (except maybe aroud older stations if slowed right down??)
Here in Sweden, not really known for high speed trains, although the SJ X2 is probably the most capable, it's service speed like most HSTs is much slower than that because of infastructure/safety. The mainline track is similar to the UK, a mix to be honest, with the smooth, noiseless expansion joint type connectors, in some parts concrete, and some parts wooden. Which is not the case when approaching a station as then it reverts to the more classic expansion-gap joined, wood sleepered track where you get the classic "clickity clack" noise.