No service between Chalfont & Latimer and Chesham while we fix a signal failure at Chalfont & Latimer. NO SERVICE between Harrow-on-the-Hill and Uxbridge while we deal with an obstruction on the track at Harrow -on-the-Hill. SEVERE DELAYS between Harrow-on-the-Hill and Aldgate due to a track fault at Wembley Park. Tickets will be accepted on London Buses via any reasonable route. GOOD SERVICE on the rest of the line.