Hi-tech satellite systems used to open train doors automatically have been failing, leaving people trapped on trains in the South of England.
The satellite system should open the doors when it reaches a station
Some commuters on trains run by Southern have become so fed up with the doors failing they have given the firm a log of when the problems occurred.
A Southern spokesman said the company ran about 1,700 trains a day and people should keep a sense of perspective.
He said it was a teething problem with new trains and would be repaired soon.
Over the last two years Southern has been introducing new rolling stock to replace its decades-old slam door trains.
The satellite tracking system monitors where trains are and should open the doors automatically when they stop at a station.
While many aspects of the new trains have been welcomed by passengers, a group who commute from the Brighton area to London have become increasingly frustrated with the problem doors.
They told the BBC the doors had been stuck shut at least eight times in the past month.
Commuter Ken Paul said on Thursday: "The most recent problem last night was quite typical.
"We got the 5.36 and the train didn't get to Victoria until six o'clock, then the doors broke at Clapham Junction, the doors broke at Horley, then we got to Preston Park and the satellite system wasn't working."
Southern spokesman Martin Walters said: "It's a new system and it's annoying people, but it's annoying us as well.
"But keep a sense of perspective on this - we run over 1,700 services every day, day in, day out.
"The system is getting better and we are bringing in these trains at a very rapid rate, they have got new technology on them and we're suffering with teething problems."