District Line commuters had their journeys disrupted by signal failures more than twice a week on average last year.
A Freedom of Information request to Transport for London (TfL) revealed 128 signal failures were recorded at peak times on the line in 2017.
Those in the morning rush hour experienced the most problems, with 74 failures occurring between 06:30 and 09:30.
But passengers travelling home were also frustrated by problems on average once a week, with the other 54 taking place between 16:00 and 19:00.
The figures come as TfL announced plans to install a new signalling and control system on the Circle, District, Hammersmith & City and Metropolitan lines as part of their Four Lines Modernisation scheme.
Richard Freeston-Clough, operations & communications manager of independent transport watchdog London TravelWatch, warned District Line commuters to expect more signal failures while modernisation continues.
“These statistics highlight the need for London Underground’s continued investment in improved infrastructure on the network as passengers using the District Line are being significantly affected by these signal failures,” he said.
“The current system is at the end of its long working life and therefore the rate of failures is likely to be on the increase.”
Work began in 2016 but the areas furthest from central London are not expected to be fully upgraded until 2022.
800,000 people use the District Line every day, including thousands of commuters from stations in south west London.
Transport for London were unavailable for comment, but state on their website: “The new signalling system allows trains to be run closer together, meaning a more frequent service and shorter waiting times, allowing more people to be carried.
“This new technology will enable us to reduce delays and improve reliability.
“The programme will allow us to operate 32 trains per hour, a 33% increase in peak-hour capacity.”
TfL figures show 13.4 million people passed through Wimbledon station in 2016, and two commuters who wished to remain anonymous gave their opinions at the station.
The first, a regular District Line commuter, revealed he was often forced to alter his journey due to signal failures.
He said: “It’s a regular occurrence, mainly around Earl’s Court.
“Because of that, I tend to go to Waterloo and take the Bakerloo Line up to Paddington.”
He added: “The signalling needs to be overhauled, I think they realise that.
“But quite often people are standing around by the platforms, nobody really knows quite what’s happening, there’s no announcement, which I think adds to the frustration.
“If there was better communication, people would be a bit more understanding.”
But another regular commuter argued the London Underground compared favourably with other countries, although he thought travel costs could be reduced.
He said: “I think the service is actually very good compared to most countries.
“I think timetables and everything are mostly accurate.
“It is on the expensive side, so I think for commuters coming in and out of London they should probably think about reducing the cost.”
