This document defines specifications covering laboratory tests for seats designed for passengers and crew in railway tractive and trailer vehicles. It concerns tri-axial rectilinear vibration within the frequency range 0,5 Hz to 50 Hz. It specifies the input test vibration to be used at seat testing. This document makes it possible to characterize, in the form of frequency response functions, the manner in which vibration is transmitted to the seat occupant. It also provides an estimator showing the behaviour of the seat in terms of dynamic comfort perceived by the seated person. Different types of excitations can be used and are described depending on knowledge of the vibration environment encountered by the seat and the capability of the vibration simulator.