Liberal Democrat Transport Spokesperson Paul Kohler says only 8 Arterio trains are in circulation at the moment.
SWR acquired 90 of them back in 2019 to boost passenger capacity.
The new fleet was revealed to the public at an event at Waterloo in November and it’s unclear why many are not in operation.
We’ve contacted both SWR and the Department for Transport for comment.
Liberal Democrat Transport Spokesperson and MP for Wimbledon, Paul Kohler said:
“It is simply unacceptable that taxpayers are footing a monthly bill in excess of £5.5m for trains gathering dust in a depot, whilst commuters in Wimbledon and the South West still have to deal with overcrowded trains.”
“Ministers must come clean on why the Arterio fleet is still not fully in service, and when this costly farce will finally end.”