NR NR/SIN/104 ISSUE 1 PDF

This SIN applies to full-depth switches in Track Categories 1A and 1 with a linespeed of 90mph or more.

Switch diamonds, bullhead switches, train operated points and spring points are excluded from this SIN.

Background and purpose

SIN 101 included the inspection of all full depth switches in running lines to record various parameters relating to the condition and set-up of fixed stretcher bar assemblies.

SIN 101 also mandated remedial works to be carried out as specified in Charts 9.1, 9.2 and 9.3 therein. The remedial works specified in SIN 101 addressed higher risk conditions linked with component defects, Flange Back Contact (FBC) and/or Residual Switch Opening (RSO) associated with switch flexure.

The purpose of this SIN is to confirm the condition of specified S&C using existing records (or arranging new inspections if necessary), apply the prioritisation rules specified in Chart 6.1, and carry out the specified works. This strategy is initially being targeted at full depth switches in Track Categories 1A and 1 with a linespeed of 90mph or more. By targeting this population of switches, risks associated with FBC and RSO will be addressed where the assets carry high numbers of axles at the highest speeds.