My TFL daily travel alert message says:

METROPOLITAN and PICCADILLY LINES: Between 2100 and 2140 on Monday to
Thursday evenings until early September, the Metropolitan line service is
suspended between Hillingdon and Uxbridge and the Piccadilly line is
suspended between Ruislip and Uxbridge. Customers are advised to use Bus
Route U2, which has been enhanced, between Hillingdon and Uxbridge.

Can anyone explain this please? 40 minutes of engineering work per day?

MaxB