Most Tube station ticket machines are only accepting bank cards. You can top up using your contactless and Oyster account, the TfL Oyster and contactless app or an Oyster ticket stop. Ticket machines at all London Overground and DLR stations are still accepting cash.
Metropolitan Line: A 30 minute service is operating between Harrow-on-the-Hill and Amersham / Chesham. A 15 minute service is operating between Harrow-on-the-Hill and Watford. A 10 minute service is operating between Harrow-on-the-Hill and Uxbridge. A 5 minute service is operating between Aldgate and Harrow-on-the-Hill due to operational restrictions.