London Midland rail operator 'let passengers down'
The head of London Midland trains has said he is "embarrassed" by the company's performance over the last four months.
Between October and the end of December almost 1,000 trains were cancelled or delayed due to driver shortages.
Managing Director Patrick Verwer said he was confident the company's problems had been tackled.
Train drivers union Aslef, however, said it was impossible to rule out further shortages in future.
Mr Verwer said London Midland had first identified it would have a shortage of drivers during the summer.
He said: "We knew we had a massive problem coming up... due to a higher turnover than anticipated.
"Training up a driver and getting them into effective operation will take at least a year, so there was this big challenge.
"People are obviously looking for a continued, punctual, good, reliable service and I'm fully aware, and everyone else is at London Midland, that we've let our passengers down over the last four months."
He said alongside training up more staff, London Midland had restructured its rotas to make them more efficient.
Last month the rail operator was told to offer a £7m compensation package to passengers.
Mr Verwer said: "It was not what were were supposed to deliver and therefore people are entitled to be frustrated.
"We need to work hard, very hard, to win them back."
National organiser for Aslef, Simon Weller, said London Midland and some other operators had become "effectively a kindergarten" for drivers.
He said it cost an estimated £70,000 to train drivers up because of the time and resources needed.
According to Aslef, London Midland pays drivers more than £10,000 a year less than Cross Country in basic salary.
"If Cross Country puts up an advert at Birmingham New Street saying it wants 30 drivers, there's virtually a stampede," Mr Weller said.
He said job satisfaction was also a reason for taking up a job with another rail operator.
"There's no chance to progress at London Midland, there's no light at the end of the tunnel.
"They do all the gutsy work, suburban routes with lots of stations. You can almost see the tail light of the train in front. It's intense work, you have to concentrate.
"It's pretty mind-numbing and monotonous."