scope:

This issue of the Specification covers the selection of signals, speed restrictions and Buffer Stops at which the provision of TPWS is required to meet the Railway Safety Regulations 1999 ('the Regulations'). As such, this specification identifies the mandatory minimum provision of TPWS to satisfy the requirements of the Regulations.

However, in addition to the requirements of the Regulations, other legal requirements exist for managing safety on Network Rail infrastructure, which may lead to additional TPWS provision. The justification for providing TPWS in excess of the minimum mandated in this specification, shall be in order to manage risk ALARP in accordance with Network Rail's Railway Safety Case. Where additional fitment has been so justified, then this will override clauses in this specification which mandate TPWS shall not be provided.

This Specification does not include the following:

• selection requirements for the application of TPWS at Radio Electronic Token Block (RETB) signalled areas. These are contained in Company Specification RT/E/S/10178 but shall be read in conjunction with this standard.

• Selection requirements for the application of TPWS+.

• Selection and fitment requirements for speed restrictions with Enhanced Permissible Speeds (EPS). Trains authorised to operate at EPS through speed restrictions will be protected using Tilt Authorisation & Speed Supervision (TASS). However, the speed restriction shall be considered for conventional (non-TASS protected) trains.

PURPOSE

This Specification describes the process for assessing the requirement to provide Train Protection & Warning System (TPWS) equipment at signals, speed restrictions and Buffer Stops as defined in the Railway Safety Regulations 1999.