The particularity of the concrete spleepers is the pre-stressing.
Cables made of steel are tightened and put in the moulds before to be cast. By relaxing, those naturally will return to their initial length and will by the same occasion compact the concrete which will have dried around them. This is what is called "pre-stressing".More about the history of railway sleepers ...
Railway sleepers began their history with the arrival of the train in 1804. The first railway made of concrete sleepers dates back from 1884 in England. However, their development really began in the early 20th, especially in Austria and Italy. After the World War II,thanks to the improvement of the way to manufacture, the design and the quality, this particular type of sleeper became more and more spread through Europe (France, UK and Germany ahead). Nowadays, they are the reference in almost every country in the world, supllanting the wooden sleepers.
Compared to the wooden ones, the concrete sleepers can hold a heavier load and a higher speed. They do not need any kind of maintenance and can resist to the rain, snow, cold and heat therefore they lifespan can be of 50 years.
- Tight drawing of cables in the formwork
- Casting of the concrete
- Curing and drying within 8 to 10 hours until the concrete becomes hard enough
- Expanding the cables
- Demoulding of the sleepers