Comms Design

RETB: Proven In-cab Digital Signalling

Efficient railway signalling for remote and rural routes

A class 66 loco fitted with RETB low cost signalling operating on the West Highland Line

Proven in-cab digital signalling for single-track railways

The RETB Next Generation system is a proven digital in-cab signalling solution designed to be affordable even on remote single-track routes with low to medium traffic.

Our RETB Next Generation Rail Signalling system is in use in the United Kingdom and is ideal for industrial and rural routes around the world.

Meeting stringent Network Rail safety and quality standards, RETB is available for a much lower capital investment than traditional signalling systems.

What is RETB? Why RETB? A-RETB – The future of in-cab signalling

RETB digital in-cab signalling is equally suited to controlling passenger trains or freight traffic with flexible on-train equipment installation. It is simple to operate for both signallers and train drivers alike, and modular equipment allows rapid maintenance, keeping down-time to a minimum.

RETB is the ideal replacement for semaphore signals, mechanical signals, coloured light signals and other types of single track train control. In fact, it does not require any kind of track side signals to control trains. RETB handles access permission for train movements allowing trains to operate safely on single-track railways without signal box personnel, physical train detection systems or substantial trackside infrastructure.

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Comms Design Limited was trusted to deliver a completely new suite of products for Network Rail UK. This integrated system supports rural routes across the North and West of Scotland.



Our roots lie in radio frequency systems design, and in building capable, software-defined RF communications products. We have been supplying innovative electronic products since 1991.


RETB Products & Services

RETB in-cab signalling is product approved by Network Rail in the United Kingdom. Each RETB network is built from a suite of products, fully supported by test equipment, spares, repairs and training.


Looking to expand your RETB system?

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Cab Display Radio


Modular Base Station Radios


Signaller’s Audio Console


Transportable Token Unit


Depot Test Unit


Cab Equipment Test Set


Hand Portable Radio


Comprehensive Documentation


Training & Support

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To find out more about Comms Design and to get a quote on our innovative rail signalling solution, get in touch now