Track Problems, Causes, Mechanisms, Solutions

Abstract

The failure of manganese diamonds (crossings) is analogous to wear in switches and therefore these priorities are equally relevant for cracked diamond (crossing)s.

A switch forms a discontinuity in any track where one is installed. It is a discontinuity with regards to track support due to the altered sleeper arrangement and during tamping operations it may require a separate operation or manual correction. A switch also forms a discontinuity for the wheel rail contact patch that may give rise to high transient vertical and creep forces (see 17.6.3.3). The high lateral accelerations to any vehicle not travelling in the straight ahead position will also cause high forces. The installation and maintenance of a switch is critical to its performance and any error may not be immediately apparent. For all these reasons, a switch will experience higher forces than plain line and the life of the switch will generally be reduced by plastic deformations, wear and/or fatigue cracks ([24][24.3])