A broken down train caused travel chaos for commuters travelling onThameslink services this evening after attempts to budge the faulty locomotive failed.
The train broke down between Kentish Town and West Hampstead, causing "major disruptions" to services between London St Pancras International and Luton.
A Thameslink spokesman said: "Attempts were made to move the faulty train using a rescue train however this was unsuccessful and the line is now expected to remain closed until at least 2200."
East Midland Trains services were being delayed by 30 minutes as a result and disruptions expected to continue until the end of the day.
But Thameslink advised customers could use their tickets on "reasonable" bus, overground and underground routes, with replacement buses ordered but not due to arrive until 10pm (GMT).
Customers affected by the fault tweeted their frustration at the delay and warned others to dodge the disruptions before it was too late.
One tweeted, sarcastically: "Train broken down at Kentish Town. Send rescue train to push it out the way. Rescue train not powerful enough. Well done everyone."
Another said: "Looks like I'll be spending my evening sitting on a broken down train somewhere between Kentish Town and West Hampstead."
Elsewhere commuters faced delays of more than a hour after trains were cancelled and disrupted across the entire South West network because of poor rail conditions as a result of "leaf fall".
Areas affected included Weybridge, Portsmouth, Southampton and Basingstoke.
A spokeswoman for South West Trains said: "We are sorry for the disruption customers have experienced this evening as a result of poor rail conditions across parts of our network."
