The Challenge:

Coming up with a solution to keep the unelectrified East Suffolk Line running after the Band III Private Mobile Radio frequency used to control trains via an Radio Electronic Token Block (RETB) system was allocated to the MOD. It was not possible to allocate new frequencies without undertaking a new safety case and obtaining new Network Rail product approval. The RETB system had to be replaced.

The East Suffolk Line runs between Ipswich and Lowestoft for passenger services operated by Greater Anglia and nuclear flask trains for the Sizewell nuclear power stations operated by Direct Rail Services. Train control on the line between Westerfield Junction and Oulton Broad North, was achieved via the (RETB) system, which was installed in the 1980s as a cost effective way of controlling trains with minimal lineside infrastructure.

The Solution:

A cost/benefit exercise carried out with Network Rail concluded that the best option was to replace the RETB system with a signalling solution designed around the principles of Track Circuit Block, which replicated the existing functionality required to run a train service.

Kier, as principal contractor, was responsible for the design, installation and commissioning including permanent way, civil, electrical, telecoms, signalling and systems. A conventional SSI (Solid State Interlocking) solution was used, which required a new signaller’s control system and Mk III SSI interlockings at Saxmundham Signal Box. Axle counters, which detect the passing of a train between two points on a track, were used in the 'long section' areas and track circuits within the station limits. A new passing loop, where trains can pass each other at a station, was also installed at Beccles Station to allow an hourly train service.

The Impact:

The new system signal system has enabled the line to remain open serving the local communities.

The new passing loop at Beccles Station has increased the capacity of the line.

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