ORR consults on Network Rail’s exemption application for the removal of TPWS at specified permanent speed restrictions
19 January 2007
ORR/01/07
Network Rail has asked to be allowed to remove the train protection and warning system (TPWS) at certain permanent speed restrictions (PSRs) where it can demonstrate that applying the requirements provides no safety benefit. The Office of Rail Regulation (ORR) has carried out an assessment of the application and is minded to grant the exemption, with conditions. Before doing so we are seeking views of interested parties.
There are approximately 1150 PSRs that are fitted with TPWS overspeed sensor loops. Network Rail’s application relates to those PSRs sites on plain line curves. It has applied for exemptions from the TPWS requirements of the railway safety regulations 1998 at 40% of the sites where its analysis shows no safety benefit in terms of mitigating over-speed derailment risk.
We have reviewed Network Rail’s application. The key reasons we are minded to grant the exemptions are:
- Whilst removing TPWS at the specified PSR sites will result in a small increase in risk in the network as a whole, other mitigation measures already exist in the form of the design of the track, the PSR, and driver training to compensate.
- There will be some performance benefits (valued at around £16 million over the next 20 years).
Notes to Editors
- The Regulations required fitment of a train protection system to prescribed locations on parts of the rail network or to trains operating on the rail network, by the end of 2003. Regulation 3 (1) of the RSR requires that “no person shall operate, and no infrastructure controller shall permit the operation of, a train on a railway unless a train protection system is in service in relation to that train and railway”.
- The TPWS fitment programme, completed in December 2003, is widely accepted as a major achievement by industry. It has significantly reduced Signals Passed at Danger (SPAD) risk – down 90% since the march 2001 baseline.
- TPWS seeks to prevent collisions by providing automatic braking if trains pass red signals without authority (SPAD mitigation), or travel at excessive speed on the approach to signals, buffer stops or speed restrictions (speed mitigation). TPWS automatically applies a train's brakes if it approaches a permananet speed restriction too fast.
- Network Rail submitted a formal application for an exemption from the Railway Safety Regulations (RSR) 1999. The regulations required TPWS to be fitted at specified locations, including all PSRs where the line speed was above 60 mph, and the speed reduction required was more than one third. Network Rail’s predecessor (Railtrack) did not apply for any exemption from this requirement, even where, as it now appears, there was very limited safety benefit from fitting TPWS at some of the locations specified. The locations covered by Network Rail’s application are PSRs curves that would experience an over-speed cant deficiency of less than 11.2°.
- Regulation 6 of the RSR allows ORR to grant exemptions from any requirement imposed by the RSR and to attach conditions to any such exemptions.
- Network Rail's application, the ORR consultation paper and other related documents are available on ORR's website at: http://www.rail-reg.gov.uk/server/show/nav.1172
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