By Wilson Walker

SAN FRANCISCO (KPIX 5) — Construction on the Central Subway in San Francisco is moving backwards Thursday after officials confirmed that crews laid miles of the wrong type of track.

The over three miles of tracks run along 4th Street from the Caltrain Station at King Street all the way north under Stockton Street to Union Square.

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“As the letter states, the rail that was installed is the standard grade rail,” explained SFMTA spokesperson Paul Rose. “In the contract, it specifies the higher-grade rail, and that’s meant to ensure that it lasts as long as it possibly can.”

If it is another setback for the $1.6 billion Central Subway project, the SFMTA wants the public to know it is not their fault.

In a letter that was first reported by the San Francisco Examiner, the agency blames contractor Tutor Perini for installing more than three miles worth of substandard rail. On Thursday, SFMTA officials told KPIX 5 it’s also the contractor’s fault for not catching the mistake earlier.

“We do rely on contractors to identify the correct material,” said Rose. “I cannot explain why the wrong rail was installed.”

KPIX 5 also spoke by phone with Run Tutor, Chairman and Chief Executive Officer of Tutor Perini. He was emphatic on three points:

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One, that the track was all purchased and installed with the SFMTA’s approval; Two, that SFMTA officials simply changed their minds about what grade of steel they wanted where; and — finally — that if track does have to be replaced, it will not affect the project timetable.

But that’s something else the two parties disagree on.

“We do anticipate that if we do have to replace any of this rail, it could add another month to the overall schedule,” said Rose.

Timing remains critical to the transit project. Just last month, transit planners were starting to look ahead to the central subway finish line. But now, they’re looking at another possible setback and a strained relationship with the contractor they’ll be working with, for at least another 18 months

It was the Chinatown Station dig that already set the project back by one year. It should be noted that delay was also centered on a dispute between the SFMTA and Tutor Perini. In that case, the disagreement was over construction timetables.

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Tutor says he and his company will file a claim against the city in the matter. Next, the city and the contractor will be inspecting the rail that has already been installed to figure out what can be salvaged.