MTR report on Hong Kong high-speed rail link derailment points finger at track design failings by consultants Ove Arup & Partners
Rail operator stops short of accusing firm of negligence, but boss Francis Li says it wrongly calculated forces track could stand
An investigation into a train derailment during testing of Hong Kong’s cross-border high-speed rail link has said a consultancy firm erred when calculating the lateral forces the track could sustain.
The inquiry, conducted by an independent panel of experts appointed by MTR, said the engineering company Ove Arup & Partners made assumptions in its design work for a maintenance track that contributed to the incident last month.
On April 3, depot staff found four wheels on the last carriage of the train had “shifted out of position” on a maintenance track during an inspection, causing mounting concerns over the express trains’ safety. Some critics said the incident would undermine public confidence in the rail link, expected to open in September.
While Francis Li Shing-kee, the high-speed rail operating chief, said the design consultant had wrongly calculated the forces the tracks could stand, the MTR stopped short of accusing the contractor of negligence.
The panel’s findings were revealed on Monday, as the rail operator submitted its findings to the government and Legislative Council about the derailment, which happened just two days after the HK$84.4 billion (US$10.7 billion) infrastructure project started its trial runs on April 1.
Ove Arup & Partners released a statement acknowledging the investigation but saying that it had nothing further to add.
MTR Corp said there were four tracks at Shek Kong that rested on I-beam assembly structures to enable staff to carry out maintenance work underneath the trains.
However, Track No 4, where the derailment occurred, was the only one that had a short curved section of 6.6 metres, out of its total length of 435 metres. The other three were straight.
“[Ove Arup & Partners] assumed the lateral forces imposed on the curved section of Track No 4 would be insignificantly small and adopted the same design ... for all of the maintenance tracks,” Li said.
“Even though the trains proceeded to this track at a very low speed, the actual lateral forces generated ... exceeded the original design assumptions and, over time, led to the I-beam assembly structure experiencing some deformation and hence widening the track gauges. The four wheels shifted out of position as a result.
“The panel and the independent railway expert concluded the incident was a site-specific issue unique to Track No 4.”
However, Li insisted the consultancy firm’s design was not incorrect, but had failed to take into account the track’s positioning and made wrong assumptions as a result.
“We will follow it up with the consultant according to the contract … We will discuss how to carry out reinforcement work … In future, we’ll have more assessments of the proposed projections,” he said.
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MTR Corp has proposed the I-beam supporting structure at the track be replaced with two reinforced concrete walls under the rails to withstand the force. The remedial work would not be started until it was approved by relevant parties, such as the government.
Li said that even with one track suspended, the other three would be able to handle the ongoing maintenance work.
MTR Corp said the other mainline tracks were not affected as they were supported on concrete slabs, instead of I-beam structures.
“After the incident, the corporation checked all tracks of the express rail link, including the mainline and other maintenance tracks, and confirmed they are in good order,” it said.
Lawmaker and rail expert Michael Tien Puk-sun accused both Ove Arup and MTR Corp of a dereliction of duty.
“It was totally unprofessional, and absolutely negligent, for the consultant to make the wrong assumptions about the track’s stress strength,” he said. “But MTR, which undertakes the operation of this high-speed rail project, also failed in its duty as it didn’t cross-check the accuracy of the consultant’s assumptions.”
Tien said the mistake was serious because the design firm might have made the wrong assumption about another area of the design that it was working on.
He suspected MTR had failed to stipulate any penalties in case of any wrongful acts by the consultant in their tender document.
The bigger problem, he pointed out, was a lack of competition in the infrastructure market, as it had been dominated by Ove Arup, and another consultant.
“If the government imposes a heavy penalty [in the tender], such as being barred from future government projects for six months, it can serve as a deterrent and also attract overseas bidders,” he said.