Weekend train services between Solihull and Birmingham are to be axed over a six-week period as part of a £75 million improvement programme.
The decision to close two of the region's busiest lines from this Saturday came as Network Rail announced the start of the next phase of the programme to improve the railway from Birmingham Snow Hill to the east of the regional network.
Buses will replace trains at the weekends between Birmingham Snow Hill Station and Dorridge, on the Warwick line, and Shirley, on the Stratford-upon-Avon line, until October 27.
Saturday services will then resume, but there will also be no Sunday service until December 2. A special shuttle train service will also operate between Shirley and Stratford-upon-Avon.
Engineering work will see the old signalling renewed with state-of-the-art equipment along 23 miles of railway and improvements to the track at Tyseley.
The railway between Birmingham and Leamington and Stratford-upon-Avon will also be closed from February 7 to February 18 next year while engineers test and switch on the new signalling equipment.
Chris Rowley, Network Rail's area general manager, said: "This major investment will mean a better, more reliable service. We have to close the railway while we undertake this major project and have been working closely with train operators to ensure replacement bus services."