Network Rail yesterday revealed details of further work on a Midland line - as it prepares to be hit with a record fine today for engineering overrun failures on the same track.

The latest work on the West Coast Main Line will subject it to closures over Easter. But the company said it was confident the programme would be completed on time, unlike Christmas when work overran for four days.

Today the Office of Rail Regulation is expected to fine NR, with the penalty expected to exceed the £2.4 million the company incurred for Portsmouth resignalling work delays in 2006.

The fine is due to be announced by ORR as it publishes the findings of its investigation into the engineering overruns - a probe which has also included a look at all NR's engineering practices.

The ORR is also likely to tell NR of areas where it thinks the company can improve. Should improvements not be forthcoming, ORR has the power to legally order certain types of work to be carried out.

It is thought the ORR might also comment on NR's progress on completing improvement work on the West Coast line in time for extra trains to run under a new timetable planned for December 2008. The Easter work will, initially, affect services between Northampton and Birmingham International on Good Friday where trains will be replaced with coaches.

Then from Easter Saturday until the end of Easter Monday there will be no Virgin Trains services running from Euston station in London to Northampton, Coventry or Birmingham.

The engineering work will also mean no London Midland services between Euston and Northampton.

West Coast services will be operating out of Euston on Tuesday March 25 but will be diverted at Rugby, meaning that journeys to the north of England and Scotland will take longer.

It will not be until Wednesday March 26 that normal services will be restored on the West Coast line.

The work is just part of £75 million worth of projects that are being completed over Easter, leading to service disruptions.

NR chief executive Iain Coucher said: "In just four days over Easter, we will deliver 300,000 hours of improvement work across the country. Around 6,000 engineers will be working day and night."