Metropolitan Line: Severe delays Harrow on the Hill and Uxbridge, Watford, Amersham and Chesham. MINOR DELAYS between Harrow on the Hill and Aldgate following the late finish of engineering work. Trains non stopping Northwick Park and Preston Road southbound only customers are advised to change at Wembley Park. Tickets will be accepted on local TfL Bus services, on London Overground services between Euston and Watford Junction and on Chiltern Railways between Amersham and Marylebone.