Tilbury Douglas has been given the go-ahead to continue its claim against Arup, in the latest stage of a long-running legal dispute over a flawed design for enabling works near Edinburgh’s Haymarket station.
The company claims Arup failed to exercise due care and skill in drawing up the design for the development of a former railyard, leading to “considerable additional expense”.
Enabling works were being carried out by Tilbury Douglas in 2013 to allow the ground level of the site to be lowered without compromising the integrity of two nearby tunnels.
Arup was appointed to prepare a design for the work which would ensure any movement of the tunnels would be predictable, and within a tolerance acceptable to National Rail.
However, issues with the design came to light after employees from BAM Nuttall, subcontracted to carry out some of the work, reported concerns about the condition of brickwork in the north tunnel.
Tilbury Douglas told the Court of Session in Edinburgh that the design adopted “erroneous assumptions” about the strength of the tunnel brickwork, did not take account of the likely presence of voids within and behind the lining of the north tunnel, and failed to make allowance for the annular and interstitial grouting that would be required as a result.
In its defence, Arup argued Tilbury Douglas had left it too long to take action, as more than five years had passed between the company becoming aware of the problems being caused by the design and court summons eventually being served in 2019.
Rejecting that argument and allowing the action to proceed, Lord Harrower said Tilbury Douglas had refrained from taking legal action as it mistakenly believed, on the basis of reassurances given by Arup, that the design was competent and there was no need for grouting, other than stitch grouting, in the north tunnel.
“These were the errors that induced it to refrain from taking legal action, and standing the words and conduct of the defender, in particular, the reassurances given, the pursuer could not, even by exercising reasonable diligence, have discovered them,” he said.
Although Arup had advised Tilbury Douglas that the north tunnel cores had confirmed the presence of soft brick, it had reassured the company, having reviewed the impact this discovery had on its model, that the design remained valid, Lord Harrower said.
“On the basis of that reassurance…the pursuer had no cause to believe it had any remedy against the defender in respect of the need for any extensive redesign or its resulting delay and costs.
“Had the defender advised the pursuer at that stage that full grouting of the tunnel was necessary, I have no doubt that the pursuer would have promptly responded to the defender, holding it liable for the resulting costs.”