scope:

This SIN applies to the inspection of all running line points fitted with fixed stretcher bars in full-depth switches.

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

Works associated with SIN101 will be in two phases, SIN 101 and SIN 1XX.

SIN 101 - This mandates the inspection of all points within the scope and requires corrective action as defined within the Actions Charts (Section 9).

SIN 1XX - This will mandate corrective action and appropriate timescales for remedial actions not specified in this SIN. It will be issued once the scope of running line points requiring attention has been analysed.

Purpose

Analysis of the results obtained from carrying out the inspections and actions mandated by SIN 099 Issues 1,2 & 3 has highlighted locations where the combination of the Track Gauge, Residual Switch Opening and Free Wheel Clearance has resulted in the Free Wheel Passage being out of tolerance, leading to undesirable Flange Back Contact.

The purpose of this Special Inspection Notice (SIN) is to measure and analyse the Residual Switch Opening and Free Wheel Passage on running line points fitted with fixed stretcher bars in full-depth switches, and (where specified) to take short-term remedial action to manage the risks and consequences of Flange Back Contact and out-oftolerance Residual Switch Opening.

SIN101 inspection results will then be analysed centrally to determine a reasoned programme of works to be carried out to renew components that may have been affected by Flange Back Contact or out-of-tolerance Residual Switch Opening.