Radio Electronic Token Block

The system is slightly similar to North American direct traffic control, which unlike RETB does not have a cab display unit.

The Solid State Interlocking controlling the system prevents the issue of any token permitting conflicting movements.

The fixed distant board on the approach has a single permanent AWS inductor which gives a warning in the cab regardless of the signal box instruction and has to be cancelled when passed.

This line was controlled by traditional electric token instruments at each station, but in January 1978 the signal telegraph pole route was brought down by bad weather over more than forty miles of track.

A new control centre was brought into use at Banavie for the West Highland Line from Helensburgh Upper to Fort William and Mallaig, and from Crianlarich to Oban.

[3] The East Suffolk Line's system underwent life extension works in 2006, but was converted to conventional Track Circuit Block with axle counters in connection with increasing the service frequency to a point where the RETB could not have handled it.

RETB was phased out on the East Suffolk Line after the last Ipswich-Lowestoft service arrived at Oulton Broad South on Friday 19 October 2012.

The rugged terrain and light line traffic made it cost-prohibitive to install GSM-R for these areas and so a new radio system, with new base station and on-train equipment, was developed.