Railway chiefs have thanked passengers for not using their services over the four-day Easter weekend.
London Midland’s service between Milton Keynes, London and Birmingham was suspended over the bank holiday because of improvement works being carried out along the line.
Although a reduced rail replacement bus service was available, the company thanked travellers for their “patience, understanding and cooperation”.
Terry Oliver, London Midland’s head of West Coast services, said: “It was clear that many of our passengers got the message to plan their journey with another operator or to avoid travel altogether. This really helped and we are grateful to those who made alternative plans.
“For those that did travel with us, our teams did a good job ensuring that customers reached their destination as quickly and easily as possible.
“I’d like to thank passengers for the patience, understanding and cooperation that they displayed over the weekend, and also during previous closures.”
The work was carried out by Network Rail, the company which manages the nation’s railway infrastructure.
This was the sixth closure to the West Coast mainline in the last 12 months, as part of an £81million project.
The line was re-opened at 3.20am on Tuesday morning.
Martin Frobisher, route managing director for Network Rail, said: “I’d like to thank passengers and those who live alongside the railway for their patience during this disruptive work.
“There is never a good time to close the railway and we apologise for the inconvenience caused. We used the time to successfully install a new bridge and bring back into use a new junction which will help give the millions of passengers who travel on this route every year a more reliable journey.
“The section of track in the Watford area is one of the most intensively used, high-speed pieces of railway in Britain and has seen tremendous growth in traffic and passengers over the last five years.
“We continue to work with all our industry partners to provide passengers with information in advance and minimise disruption as much as possible.”