A major blunder has been discovered at a new £2million railway bridge in Dumbarton, it can be revealed.
Network Rail replaced part of the structure over Bonhill Road in October last year – which caused travel chaos at the time.
But more disruption could be ahead for frustrated residents after bosses confirmed the new structure will need even more work as it has been installed TOO HIGH.
As a result, train drivers have been told to slow down on approach to the bridge.
Network Rail has confirmed the embarrassing mistake this week but stressed that it does not pose a safety risk.
A source told the Lennox Herald it is a “costly nightmare”.
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He said: “With all the preparation that has gone into this bridge removal and replacement it is absolutely incredible that the bridge was built too high.
“This after all was an operation that was a long time in the planning due to the requirement to both remove the existing bridge, install the new bridge, and have the trains all running again in a 54-hour weekend shutdown possession period.
“Quite how the reported 125mm height incompatibility arose will remain to be established but clearly someone was not talking to someone else.
“Even more clearly, the design checks did not recognise the problem until it was too late. This is a failure in process.
“There will be much scratching of heads and hunting for the guilty. This will be very costly to repair. Currently a section of the line is under a speed restriction order restraining trains to a maximum of 20 miles per hour.”
The engineering expert told how it is likely that the line may need to be closed for another weekend to fix.
He explained: “To resolve the problem it may be that Network Rail will have to jack up the entire bridge, remove the bearings and then reduce the concrete bearing plinths.
“With no doubt the line requiring to be closed for another weekend, this will be a costly nightmare and once again the people using the west coast line will be denied a rail
service.
“The need for a speed limit and another weekend closure couldn’t come at a worse time when the network timetable is already under stress.
“At least however final safety checks discovered the height incompatibility and a speed limit was able to be put into place to keep the service running.
“The closing down of the west coast line does not bear thinking about.”
The new bridge deck was replaced toward the end of October last year, with various road closures taking place between October 13 and October 23.
Network Rail said the work was vital as the old bridge was beginning to degrade.
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Trains were cancelled on the line over a weekend but there was further disruption to commuters on the Monday morning due to delays to the work.
Passengers were told to arrange alternative travel as ScotRail was unable to provide a bus service to replace the early trains.
Jackie Baillie MSP expressed her concern over the error.
She said: “It is disappointing that following weeks of disruption in October, when the bridge was being replaced, there could be even more disruption for residents and passengers who will have to suffer yet more works at Bonhill Road rail bridge.
“This mistake is causing yet more disruption on our, already chaotic, rail network as trains are being forced to slow down at this section of the line.
“Network Rail should be trying to claim back money from AMCO Giffen, the contractor, to ensure that the public purse is compensated for their error.”
A Network Rail spokesman said: “The new bridge deck has been installed slightly higher than designed.
“We are currently assessing the best engineering solution before carrying out works to correct the issue.
“There is no safety risk to the structure.
“There’s a speed restriction in place, but it’s not for safety reasons. We always put speed restrictions on after we replace a bridge while the new track etc settles into position.
“On this occasion we’ve kept it on due to the slight misalignment.”
We contacted AMCO Giffen and they declined to provide a statement.
