Telent Radio Electronic Token Block (RETB)

Fenix Signalling delivered the first part of a major RETB (radio electronic token block) upgrade project in the West Highlands of Scotland.

The upgrade was made necessary by OFCOM’s decision to reallocate the operating frequency in this region for digital TV throughout Europe. The project, commissioned by Network Rail and led by Telent (telecoms services), required changes to be made to the frequency of the base stations. However, the wider implications included the development, modification and renewal of depot, engineering and trackside equipment to provide a fully operational communications system.

Fenix Signalling was responsible for all the signalling and testing works in the project. The company initially completed trials at two sites. Subsequently, work was completed at 19 sites on the West Highlands Line, totalling 165 miles. This included modifications to the TPWS (Train Protection Warning System) power supplies to enable the change of frequency.

Various challenges needed to be overcome along the way. Many of the locations were extremely inaccessible, requiring a journey of around five hours in a 4×4 between each and the winter weather conditions contributed further to these difficulties.

Success of the first phase of the project was thanks to the close collaboration between the signalling and telecommunications disciplines, and the teams at Fenix and Telent worked very effectively to achieve this.

2016 will see the Far North Lines, totalling 230 miles, upgraded for the frequency change and the interlocking at Inverness upgraded.