TASS-ERTMS - Compatible Control of Tilting Trains

In September 2004, Britain's Virgin Trains introduced radical new timetables for their West Coast and Cross Country services, with more frequent services and significantly reduced journey times. This was made possible by the use of 200km/h tilting operation by Virgin's fleets of electric and diesel trains. To mitigate the additional risks that these tilting trains potentially introduced to the rail network, continuous speed supervision and safe switch on/off of tilt was provided by the TASS (Tilt Authorisation and Speed Supervision) system. TASS was developed by ALSTOM Transport as part of its Virgin Pendolino train contract, with onboard equipment also supplied for the Bombardier Super Voyager diesel trains. TASS uses ERTMSbased on-board equipment to carry out the required functions according to telegrams received from passive Eurobalises on the track. The 194 sets of on-board equipment and the 750 Eurobalises now installed are enabling around 420,000 km/week of tilting operation, giving very rapid experience of the performance of ERTMS equipment in full commercial service.