Disruption to rail services is set to continue after a train came off the track when it hit a landslip caused by torrential rain.
The 6.19am London Midland service from Milton Keynes to London Euston partially derailed in a tunnel near Watford Junction at around 7am on Friday.
Another train travelling in the opposite direction "gave a glancing blow" to the derailed train, Network Rail (NR) said.
Two of the four lines of the West Coast mainline have been out of action since the incident.
A spokesman from NR said the trains have now been removed from the tunnel and safety check and repairs to the landslip and infrastructure are being carried out.
"We hope to have normal service through the area in time for the Monday morning peak. Passengers are advised to check nationalrail.co.uk before they travel for the latest information," he added.
Francis Thomas from London Midland said they have been "running a reduced service" across Saturday owing to the two lines still being blocked.
"The plan is to get the two tracks clear and repaired for a full service on Monday morning, but that is subject to Network Rail doing all the work that they now need to do," he added.
"We are very much in the hands of their engineers to repair the tracks."
Rail provider, Virgin Trains, which also operates on the line, advised customers on their website that trains running through Watford Junction and Milton Keynes Central may be cancelled or delayed by up to 20 minutes.
The company said "disruption is expected until the end" of Sunday.