SYSTEM OVERVIEW

Following the decision to build a new high-speed link between central London and Heathrow Airport, Siemens were awarded the contract to provide the train sets. The audio communications elements required, in addition to the usual Public Address and Crew Communications, interface to and co ordination with, the extensive visual elements provided by Siemens. In 1995, GAI-Tronics was awarded a design and build contract for deliver of 14 train sets of equipment during 1997.

SYSTEM FUNCTIONALITY

The requirement from Siemens is to provide PA receivers, driver’s control panels and passenger call for aid units. In addition to the usual audio pair, additional wiring is utilised for transmission of data to and from the train management system.

A digital speech facility is provided via a drivers keypad for pre- recorded messages and ‘jingles’, plus a walk through test message facility.
Because this is a totally new concept of train design, the safety case requirements prior to the train being allowed to run is extremely onerous requiring the communications system, which is considered a safety critical item, to undergo extensive in house testing at GAI-Tronics prior to dispatch.