The first high speed train made at Hitachi's Newton Aycliffe plant has gone into service today, but suffered technical problems.
Operating on the mainline between Bristol and London Paddington, the train appeared to break down twice, causing delays of around 45 minutes.
There was also a problem with the air conditioning. Hitachi says it remains an historic day but it is investigating what happened.
The new fleet has cost £5.7 billion.
The train was due to leave Bristol Temple Meads at 6am but did not set off until around 6.25am, according to rail website Realtime Trains.
The Great Western Railway service, which was carrying Transport Secretary Chris Grayling, industry bosses and regular commuters, arrived at London Paddington 41 minutes late.
During the journey passengers reported a leak from an air conditioning unit.