After 90 years of service, a station box from the pre-war era of the London Underground will earn a place in a museum, to be replaced by newer technology that will allow train frequency to be increased by 33 per cent.

The Edgware Road station box, built in 1926, ensures safe running of trains on the Circle and Hammersmith & City lines. As the box slowly nears the end of its active service to make place for newer technology, the Railway Heritage Designation Board has recognised it as being an item of national historic interest.

The box's mechanical 'K-style' lever frame currently operates the interlocking of signals and points at the complex junction used by the Circle and Hammersmith & City lines.

"Upgrading the Circle, District, Hammersmith & City and Metropolitan lines will enable us to increase capacity for millions of our customers,” said London Underground's managing director Mark Wild, explaining why the heritage cabin will be ‘honourably retired’.

"We aim to provide safe public access to the cabin in the future so that Londoners can share in this unique part of the capital's transport history.”

The new digital signalling system to replace the mechanical one of the old cabin will will make it possible to reduce the distance between trains. By early 2020s, frequency of trains running on the Circle and Hammersmith and City lines should increase by 33 per cent as a result.

Mike Ashworth, London Underground's design and heritage manager, said the switch to new technology will benefit costumers and improve efficiency of operations. However, he said, the old technology will be preserved.

"This unique signalling cabin harks back to the earliest days of London's transport network, being originally built and used by the Metropolitan Railway in 1926,” he said.

"Ensuring we understand and preserve the heritage of the world's first underground railway - with all its surprising historic quirks - is key.”