Rail Track?

Question

In the earlier days, Wooden sleepers were used below the rail tracks. They have now been replaced by concrete sleepers. What are the advantages of using the concrete sleepers when compared to the wooden sleepers? Also, why is blue metal used near the tracks?

Answer 1

concrete does not loose it's shape or trueness like wood and lasts longer and no environment problems from creosote[ the preservative added to wood as for blue metal i don't know what you are asking about, hope this helps some what

Answer 2

Above answers about concrete vs. wood (often Oak or Pine) sleepers/ties are correct.

The only "blue metal by the tracks" I can think of is "Blue Flag Protection". In the U.S. when there is a person or a crew working on or around locomotives or freight cars, a blue "flag" must be placed on the rail in front and/or beind the equipment. These "Blue Flags" are typically painted steel and clip onto the rail (there are other variations, but i have imitted them for the sake of clarity). Only the person who placed the flag or someone authorized by the orginal person may remove this flag.

Answer 3

Timber is getting scarce in the UK and the EU, and it is now much more costly than concrete.  The manufacture of cast concrete sleepers (called "ties" in the US), requires less skilled labor and uses less wear-prone tools.  Also, concrete sleepers last longer and do not need to be impregnated with preservatives, which may be toxic to the environment.

Finally, concrete sleepers are more uniform and can be used to build a high-speed rail line more easily.

So the answer is simple:  concrete sleepers cost less both to make and to use than wooden ones.

This is less so in the US, where the supply of timber is more liberal, and so wooden ties are in greater use in the US.  Eventually, all sleepers/ties will be concrete.

As for the mystery about "blue" metal:  it is only guesswork, but one wonders if you are not noticing that chairs, bolts, keys, and other components of the track made from steel may seem to take on a "gun metal blue" appearance over an extended time.  This would be because a species of carbon steel with some adulterant has been used that takes on a "gun metal" caste.  That's only a guess.

Answer 4

I know I'm not going to give you the greatest answer. But I did work for Sperry Rail and tested all over the east coast and asked the same question.

What I was told was that they were obviously more environmentally friendly (no wood) and plus the creosote (or chemical) needed to cure the ties obviously leaked out into the ground overtime, not an issue with concrete.

One track worker told me that the type of concrete used is different also. And they are easier to replace (which seemed to be the best part, from the workers view). I understood that the "railroad bed" had to be really firm and solid.

I don't think the rails out in the swamp areas are using concrete, they still use wood because it is more flexible and tolerates the swampy ground better. I noticed the concrete ties were more on the newer, well built commuter metro system. Like Metro North in New York,

I don't know about the blue metal? what are you referring too? I think I remember blue plates used to secure the rail to the ties, idk. I would say the "blue metal" is more rust resistant.

Answer 5

This is an interesting term.  I have never heard Rail Ties beeing called sleepers.  I had to look that up.

Anyhow, as the other folks have mentioned, the concrete ties offer better stability than the wood ones do.

This biggest advantage though is the fact that they also do not deteriorate as quickly with the constant pounding they are receiving.

Here in the US, the concrete ties are becoming more common place as the need for higher speeds on the rails increase.  

But for our railroads here, the biggest motivation for their replacement is cost.  They are indeed slightly more expensive initially to procure, however, because they last twice as long, their cost is made up on the other end with fewer needs for replacement.

Answer 6

Concrete is more durable than wood. The wooden sleepers had to be heavily treated with creosote and had to be replaced every few years.

Concrete sleepers last longer. The type of fixing rail to sleeper has also changed. In the days of wooden sleepers the rail rested on a cast-iron moulding called a chair, which was bolted to the sleeper. The rail was held in place by a wooden or metal wedge known as a key.

With concrete sleepers the rail is fixed to a metal base on the sleeper with twisted steel clips known as pandrols. These hold the rail in place and resist  the 'creep', that is, the tendency of the rail to move in the direction of train travel.

Answer 7

By your wording I am assuming you are referring to rail in the U.K., I can only base my answer on my experience in the 'States so it may not be the same where you are.

Most ties are actually still wood, they only use concrete in very heavy density main lines where wooden ties wear out faster.

Branch lines, sidings, yard tracks, most of these still use wooden ties.

Concrete is heavier and holds it's position in the roadbed better so they can be spaced farther apart if the rail is sufficiently heavy for it.  

I believe wooden ties are normally spaced on 18" centers and for concrete they use 24" centers.

I see some special "U" shaped clips on concrete ties but they are not pandrol clips, we use those on curves with wooden ties, they have special tie plates for them.

Concrete has to be ballasted much more firmly or it breaks, and if a bit of equipment such as a dragging beam or wheel chips the top surface of a concrete tie it will develop a break in a short time.

Concrete costs about twice as much as treated wood ties, (at least that's what a roadmaster told me)

But they last much longer if properly maintained and hold curves better so the track doesnt need realigned as often.

A matter of economics, making concrete isnt really much better environmentally than treating wood.

I have no idea what blue metal you would be referring to, I have not seen that. interesting, all that I can think of is some sort of rust or corrosion preventative.