Primary Suspension Primary suspension

 Primary Suspension Primary suspension is implemented by two units (see FIG. 4-3) of two steel coil springs (internal (4) and external (5)) laid out on the control arm upper part (13) by a centering disk (8) and adjustment shims (if required). The suspension is also completed by the following components:  A control arm (13), fitted with twin-layer elastic joints (12), connecting the axle bearing to the bogie frame and transmitting, not stiffly, lateral, longitudinal and part of the vertical forces;  A vertical damper (14). Rubber elements (2) separate the primary suspension from the bogie to realize noise reduction.