9. Glossary – Definitions

Caisse ; body

A rail vehicle structure comprising all the equipment for the motive power units and the passenger and/or driver accommodation for the passenger or self-propelled units.

Adhesion; adhesion

Fundamental quantity characterizing the traction and braking capacity of a rail motor vehicle. It is the ratio between the force exerted by the wheel on the rail and the load supported. As the coefficient of friction between steel wheel and steel rail is low, the adhesion coefficient is a maximum of 0.45 at start-up, decreasing with speed. To be on the safe side, it is taken to be between 0.10 and 0.15 for braking forces