Commuters travelling to and from a major London railway station are being told to continue to expect disruption until at least midday.
On Friday evening a “trespass incident” saw all services into London Euston halted after emergency services helped someone near Wembley Central station.
British Transport Police said a male had been “taken to a place of safety”.
National Rail warned some of Saturday’s services may be cancelled due to displacement of trains and staff.
Power was cut on some trains, with one commuter describing how passengers were stuck on a train.
London Northwestern Railway, London Overground, Southern and Virgin Trains were all affected.
National Rail said anybody unable to travel on Friday night could use trains on Saturday for no extra cost.