AN INVESTIGATION by Network Rail into substandard track work by Mowlem is considering plans for all future renewal work to be signed off by its own in-house engineers.
On January 10 Mowlem handed back a section of track on the West Coast Main Line at 5.30 am.
At around 5.30pm a driver reported a bumpy ride and, after an inspection by Network Rail engineers, a section of the line near Watford was shut while remedial work was carried out.
Network Rail staff found that clips that secure the track to the sleepers had come off on the section of line and Mowlem was suspended from carrying out all renewal work across the network until further notice.
Construction News understands that Network Rail is looking at changing the rules so that one of its own people must check and sign off all renewal works.
Under existing rail regulations a 'qualified and competent person'must check and pass work to make sure it has been done properly.That person can currently be from the contractor carrying out the work.
A Network Rail spokesman said: 'We are taking it very seriously.We want to get to the bottom of why it happened.
'The clips were put back on and we are holding an investigation into how this could happen.
'The problem only covered two sleeper lengths and trains in this area are restricted to a speed of 50 mph anyway.
'The track should not have been in this condition but due to the nature of the defect and the low speed in place at this section of track we do not think there was a safety issue.'
Network Rail confirmed that it has the power to remove contractors from carrying out work on the network if the situation is serious enough.
The preliminary findings of the investigation are expected to be made public this week.
Mowlem has a rolling renewals contract on the West Coast Main Line worth around £25 million over three years.
All its structures and other civils work for the not-for-dividend operator will carry on as normal.
Mowlem said: 'Network Rail has launched an investigation into this incident and we are co-operating fully with it.'