Major work replacing tracks on two underground lines will begin this weekend - with more than 20 days of closures to come this summer.
Transport for London will carry out the engineering work this summer to replace track on the Uxbridge branch of the Metropolitan and Piccadilly lines from Saturday July 19.
On Saturday and Sunday July 20 on the Metropolitan line there will be no service between Wembley Park and Uxbridge or Northwood while points are replaced at Harrow-on-the-Hill.
On the same days there will be no service on the Piccadilly Line Rayners Lane and Uxbridge.
More work will be carried out between July 19 and August 10, which TfL says is the quietest time on the Tube network and will reduce the number of weekend closures.
During the work, tickets will be accepted be accepted on local buses and a rail replacement bus service will be in operation connecting with the Central line at West Ruislip.