Improving the laying and maintenance of ballast requires numerical models that take into account all track components. “To decide how thick the layer of aggregates should be, we have to study their interaction with the roadbed in a single system that must be globally modelled”, says SNCF researcher François Quétin. Ballast does not behave uniformly over the full length of a rail line, confirming the influence of the substratum. In some places on the Paris-Lyon high-speed line, the ballast has penetrated and been “contaminated” by the sub-base material, diminishing its performance (see the inset “Supertrack”). Higher speeds, frequencies and axle weights could accelerate this phenomenon and make it more dangerous.
|
|
