BART trains were delayed this morning as the system recovered from an incident in the Transbay Tube in which a train came apart.
The nine-car train split into two pieces, a five-car train and four-car train, shortly after 6:20 a.m.
BART spokesman Linton Johnson said that the cause of the break is still under investigation.
“We know that there was some sort of metal fracture that caused a portion of the coupler that joins the two cars together to fail,” he said.
The solid-metal part of the coupler that failed was “bigger than a body-builder’s arm” and “designed to last a lifetime,” according to Johnson. It was just installed in January 2009.
The five-car section of the train was removed first with the operator on board and another operator then boarded the second, four-car portion, and moved it out of the way as well.
“We’re in contact with the manufacturers to find out how this could have happened,” Johnson said. He did not know if BART has a warranty for the part.
The manufacturer, a Pennsylvania-based company called Wabtec, was unavailable for comment.