Asbestos Ballast

In asbestos ballast, asbestos fibers, after wetting and compaction, form strong structural bonds between the rock grains, and a crust impermeable to atmospheric water and weeds forms on the surface of the prism.

In accordance with TU 32 CP-782–92, asbestos ballast is used to ballast the main tracks of all classes and station tracks. A sand-gravel mixture from screenings of crushing serpentinite can be used. These are ordinary, unenriched asbestos waste from the Asbest concern ( Bazhenovskoye deposit ).

The use of asbestos ballast in the upper layer of the ballast prism on high-speed lines is not allowed.

Asbestos ballast cannot be considered promising material for ballasting the main routes for the following reasons:

• cleaning and its reuse on the way (unlike crushed stone) is impossible, labor-intensive cutting and transportation of contaminated mixture is necessary;
• with a large number of dusty particles (less than 0.16 mm more than 10%), as well as with an insufficient content of asbestos fibers (less than 1%) and a thickness under the sleeper of less than 20 cm, asbestos ballast does not work satisfactorily;
• the need to bury huge volumes of contaminated asbestos ballast, which has served its time and is cut out of the way during major repairs with the replacement of crushed stone, is a serious environmental problem;
• sanitary standards require that all types of work with asbestos ballast (loading — unloading, laying in a way, knocking out) be carried out with mandatory measures aimed at reducing its dusting, which are difficult and rarely feasible in practice (meanwhile, inhaling small fibers of asbestos is dangerous to health people).

In connection with the foregoing, the use of asbestos ballast in recent years has been limited to sections of the track with intense clogging of bulk cargo, as well as in the Urals . In the 1970s, there was widespread use of asbestos ballast, the laying of which was considered rational everywhere, even with a carriage range of 2-3 thousand kilometers or more. A significant part of the length of the main routes was laid on asbestos ballast. At present, the efficiency of this ballast in many sections of the track has been exhausted due to its extreme pollution. Such ballast has to be cut out and replaced with crushed stone ballast .

• Railway track / T. G. Yakovleva, N. I. Karpushchenko, S. I. Klinov, N. N. Putrya, M. P. Smirnov; Ed. T. G. Yakovleva . —M .: Transport. 1999.405 p. - ISBN 5-277-02079-9 .