Concrete falls close platform

Engineers are dismayed that concrete has fallen from a ceiling beam in Auckland's $211 million Britomart underground railway station, less than two years after the centre opened.

Platform One remained closed to trains and passengers yesterday, after two pieces fell from the beam at the beginning of the Tuesday afternoon transport peak, but it was business as usual on the station's other four rail tracks.

The platform was roped off after a piece of concrete weighing almost half a kilogram hit the roof of a train then bounced on to the platform.

A smaller piece from the same cross-beam was found on the rail track about 6m below the ceiling.

Although there were few people left on the platform after the train's departure, a spokesman for station management agency Auckland Regional Transport Network acknowledged that the larger piece could have caused injury.

Bob Lupton, the network's risk and safety manager, said a visual inspection of other beams above the track and of a large air-ventilation chamber inside the ceiling did not reveal anything else untoward.

But he said the agency took any potential threat to public safety seriously, and called a meeting of about 12 structural engineers yesterday to plan a fuller investigation throughout last night.

A cherry-picker was used for that investigation after train services stopped for the night, and the exercise may have to be repeated tonight to check beams above Platform Five.

That platform remained open yesterday, after its beams passed Tuesday night's visual inspection.

Mr Lupton said the engineers had yet to discover the cause of the beam failure.

It may have been vibrations from trains or defective concrete - or a combination of the two.

His agency's acting chief executive, Kevin Brown, said all buildings had problems and there had been some moisture leakage around the Britomart's skylights which had been remedied.

"But this one's a little bit out of the ordinary - it's a bit out of left-field," he said of the concrete failure.

Although Britomart is owned by the Auckland City Council, Mr Brown's organisation manages it, with the region's other railway stations and ferry terminals.

The Labour Department and Land Transport NZ have been told about the incident. A spokeswoman for regional rail operator Connex said the platform closure had not interfered with train movements.

She understood another safety inquiry - by the Transport Accident Investigation Commission into a fire last week on a crowded train operated by Connex just outside the rail tunnel leading to Britomart - was close to completion.