Why There Is No Ballast on High Speed Rail Track?

Ballast Rail Track

Ballast refers to the gravel or crushed rock paved on the road or railway subgrade, it is mainly used in railway subgrade. Ballast is one of the main components in the railway transportation system, used to support the railway sleeper and rail track. Before laying tracks, a layer of ballast is needed to pave on the railway subgrade. The use of ballast is very available for water drainage and the track position adjustment. Rail ballast can distribute the pressure pushed by the sleepers, steel rail and vehicles, to the roadbed. It can reduce the vibration and noise caused by the train, increasing passengers ride comfort degree.  

Function of Rail Ballast 

• Distribute the pressure and shake when the vehicles passing by, keep the gauge invariant.
• Reduce the noise and improve the comfort of the passengers.
• Easy to drain water with good permeability.

The Disadvantages of Ballast Rail Track 

Why High Speed Rail Adopt No Ballast Rail Track?

• The maintenance time of normal rail road track and the ballast is usually at day time, and the maintenance work is carried during the operating line gap. The vehicles may limit the speed during the maintenance period. Because the speed of HSRs is high, limit the speed is impossible, the carry out of maintaining work is not so ideal as normal rail. It is reasonable to use concrete track instead of ballast track.  
• The concrete track is smooth than the ballast track, so the noise is lower and the passengers can feel more comfortable and steady. 
• Avoid ballast splashing, running on the concrete track can ensure the problem of no ballast splashing, securing normal movement of high speed rail.