Trains on London's longest tube line will undergo a £112m upgrade with an aim of to improving reliability and reducing delays.
Roughly 800,000 people use the Central Line every day, on trains which were brought into service between 1993 and 1995.
The carriages are just over halfway through their nominal 40 year design life, but the technology has already been superseded according to a Transport for London (TfL) proposal document from 2016.
The same document sights the reasons for the poor performance and low customer satisfaction with Central line trains as "poor design, poor manufacture or obsolescence".
The line runs from West Ruislip in the west of London, through the centre of the city and onto Epping in the north east.
London Underground currently spends around £8m a year "repairing or overhauling traction motors" adding that the line loses more 'customer hours' than any other due to poor reliability.
The renovations are part of the Central Line Improvement Program (CLIP) which aims to improve the performance of the fleet while lowering the operating costs.
TfL has awarded the contract for replacement motors and traction control equipment as well as on-going maintenance to Canadian train manufacturer Bombardier.
The contract is expected to be completed in 2024 by the train company behind the new train stock on the District, Circle and Hammersmith & City Lines and the manufacturers of the new Crossrail trains.
The project will see Bombardier overhaul 85 eight-car trains on the network, which are expected to remain in service until 2033.
Mark Wild, managing director of London Underground, said: “The Central line is one of the busiest and most important lines on the London Underground network.
"We are making a number of improvements to reduce delays and make the line more reliable for our customers.
"Installing new motors is one of the most important parts of this work, and will mean we can deliver a more reliable service to our customers, which will in turn boost capacity.”
Richard Hunter, managing director of Bombardier Transportation UK, said: “Bombardier has a long history of working with London Underground, and we continue to provide cutting edge technology across the tube network, playing a vital role in keeping London moving.”
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