London Midland disruption: 30 services affected
More than 30 London Midland services were due to be either cancelled or disrupted on Saturday because of a company-wide driver shortage.
Lines between Birmingham and Euston, Coventry and Nuneaton and Wolverhampton and Walsall have been affected.
The cross-city line, which calls between Lichfield, Birmingham and Redditch, has also been disrupted.
London Midland has apologised for the disruption, which is expected to continue until mid-December.
It said on Saturday, buses would replace its train services between Nuneaton and Coventry from 15:40 to 18:30 GMT.
London Midland has blamed a temporary shortfall in qualified drivers and "short-notice sickness".
It said that on Saturday six shifts were affected, which meant 31 of its 1,200 trains were being cancelled or disrupted.
The company has said new trainee drivers will be qualified by mid-December.