Railway Dynamics and Wheel-Rail Contact. Guiding Principles, Running Behaviour and Damage Patterns

The rail vehicle dynamics is one of the most complicated and important dynamic systems to be studied and optimized in engineering. The track-vehicle interaction system analysis must consider that (i) many flexible bodies (carbody, bogie frame, wheelsets…) comprise the system, (ii) the different bodies of the vehicle (single or multi units vehicle) are connected via suspensions and constraints, (iii) a moving and complex wheel-rail interface connects the vehicle with the track, (iv) the track has its own geometry and characteristics, (v) the inter-action between the mechanical system and other subsystems of the vehicle must be taken into account (traction and braking system, active systems, tilting technology, smart suspension, steering systems on the wheel set or bogie) and (vi) the operation conditions, country standards & regulations and the presence of relevant infrastructures (bridges, sub-track…).

To this complexity is added also the continues change, in time and distance, of track geometry, of the wheel-rail contact geometry (wheel and rail profile evolution), friction conditions, etc. ; hence non conservative frictional forces are generated by relative motion in the contact area and in the other interfaces/links between different bodies of the system.

Growing demand of operators and railway infrastructure owners for faster, very comfortable and track friendly rail vehicles (i.e., low Track Access Charges-TAC) and short time to market ; these are the last challenges that railway dynamics engineer have to face. All this complexity and the design challenges ask for good understanding of the system, high technical competences and wide experience on the field, appropriate simulation models, advanced tools and methods to be used during the design phase.

The technology of this complex system rests on a long history. In the late 18 ^th and early 19 ^...