The rail crack was detected at about 9:45 Thursday morning underground, 120 feet north of the Lake Merritt station. It could not happen at a worse spot -- a major rail intersection where all five BART lines meet.
"We wanted to make sure our passengers are safe, so we terminated service as soon we saw evidence that there might be a crack," said BART spokesman Jim Allison.
Riders were detoured on special shuttle trains, resulting in delays of an hour or more.
"We had to transfer a couple times and we had to wait for other trains to clear the tracks," said BART rider Paula Johnson.
By noon, workers had made temporary repairs to the rail, enabling regular train service. The cracked rail is symptomatic of an aging infrastructure.
"A new rail wouldn't crack, but an older rail does," said BART spokesman Linton Johnson.
Last May, a transformer caught fire in a Hayward BART yard causing major delays for months at some stations. That is also evidence of the need to replace aging power equipment.
BART is using $18 million of state bond money to replace old circuit breakers at its older stations. It is a priority since the firm that makes the circuit breakers quit business, so there are no spare parts if there is a power failure.
"So the lights would go out, the equipment at the station would go out. We'd have to shut down the station," said Johnson.
However, BART's number one priority is to replace its entire fleet of 669 train cars with a high-tech fleet.
"We've got about $8 billion in needs and not all the money. About a $2.5 billion shortfall," said Johnson.
Getting the rest of that money is difficult. BART says the regional funding formulas of the Metropolitan Transportation Commission favor building highways and not mass transit. Washington has been little help as well.
"Congress has traditionally favored new starts as opposed to adding capacity or dealing with the problems of older systems," said Tom Redulovich, BART's board director.
BART's money comes from a variety of funding sources -- the feds, the state, the counties, etc. However, getting that money is difficult, so they have had to rely on the fare box. The next increase is January 10.