Metropolitan Line: A 30 minute service is operating between Harrow-on-the-Hill and Amersham / Chesham. A 15 minute service is operating between Aldgate and Uxbridge and between Baker Street and Watford due to operational restrictions. A 30 minute service operating between Chesham and Watford. If your journey is essential, take the first train and change where necessary. Public transport should only be used for essential journeys.