A row between Network Rail and engineering agencies over wages may have contributed to delays to the Christmas rail upgrade programme.

Network rail refused to take on extra workers at high wages over Christmas, despite the threat a skills shortage posed to track upgrade deadlines.

Work on the West Coast Main Line, which ought to have finished by the end of 31 December, overran by three days, causing delays for thousands of rail passengers.

Network Rail announced it would be holding separate meetings with each contractor involved in the delayed work to investigate what happened, but as Building went to press on Wednesday the company had still not contacted some of the key contractors on the delayed Rugby station project, including Scott Wilson, Atkins and Nuttall.

Unions claim a shortage of skilled workers meant that labour agencies were charging up to £1,400 a shift.

A union source said: “Network Rail didn’t bring any more people in because it would have cost them a fortune. When you’re paying guys that much to hammer nails in, you have to wonder about the lack of training in this industry.”

A spokesperson for Network Rail said: “We are meeting Bechtel and Jarvis this week and will meet others next week.”