The company said the shortfall in qualified train drivers should be addressed by mid-December, Sky News reported.
"We are being open and transparent so people can plan their journeys. Not all the disruption caused today (Saturday) is as the result of train driver shortages," a London Midland representative said. "We have a dedicated team focusing on delivering the train service on a day-by-day basis and as a result we have been able to run a near-normal timetable on all but a few days, compensating for the shortage with drivers who have volunteered for overtime."
Phil Davis, spokesman for the passenger group Travel Watch West Midlands, said, "The situation seems to be getting worse and it calls into question the competence of London Midland."
Davis urges commuters and other organizations to complain to the government about the "unacceptable" service.
"We need a service we can rely on," he said.