A 3D Contact Force Safety Criterion for Flange Climb Derailment of a Railway Wheel

A revision on the railway safety criteria evolution has shown that the fundamentals of wheel/rail contact phenomena have not been completely addressed. Limitations encountered on the available criteria for safety against derailment have motivated a deeper analysis on the wheel rolling mechanism. The contact mechanics were completely modelled with two tangential components, lateral and longitudinal forces, including spinning effects. An extended three-dimensional formula for the railway wheel flange climb derailment process is derived. Results show that calculated values agree with the classical formulation, and extend its application. This formulation allows the identification of L/V limit values for a three-dimensional rolling-contact mechanism. It can help to identify more reliable limits, relocating the safety margin for the dynamic operation of a railway vehicle.