The Bakerloo Line and London Overground will be back up and running shortly.
Network Rail engineers have spent more than two hours battling to repair a broken rail at Wembley Central station.
The work has now been completed so the service will be restored as soon as the engineers have cleared the track.
Since 12pm the Bakerloo Line has been suspended from Stonebridge Park to Harrow and Wealdstone and London Overground has been suspended from Willesden Junction to Harrow and Wealdstone.
Tickets are being accepted on local buses.
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