OAKLAND, Calif. (KTVU) - Early morning BART commuters on the Dublin and Fremont lines were faced with delays Thursday due to a cracked rail discovered shortly before the system was about to open.
Rail cracks present a danger if they go undiscovered or unrepaired, but in this case, the system worked as it should. At about 3:30 a.m., a track maintenance crew, heading back to the shop for the system's 4 a.m. opening discovered a crack in the rail.
Safety rules presented BART with a "no go" situation and immediate repairs were ordered. That required double tracking which slowed down the process from 4 a.m. to 6 a.m.
"We found a crack in the rail and it was caused by small micro cracks in the bolt hole -- bolts that hold down the rail and the rail sections -- those bolts can cause little micro cracks that then turn into a bigger crack," said BART Spokeswoman Alicia Trost.
Micro cracks are often very tiny or microscopic breaks in the steel which can grow quickly if agitated enough. Most often, temperature swings can make rails crack, especially as they age.
Repeated mechanical stress, such as wheels rolling over rails, can also cause micro cracking. Corrosion, salt, chemical or rust, can do it as can deficiencies in the formula of the rail steel.
"It's exactly why we do these inspections every night of the week, to stay on top of those issues and to replace the rail. If it was found maybe at 1 a.m. in the morning, we would have taken care of it. The riders would have never even known," said Ms. Trost.
In order to address the micro cracking incidents that delayed the system this morning or the many worse things that could happen if they're not addressed, BART is on a 12-year program to replace 10 miles of track every year.
"Since measure RR had passed we've really been focusing on those Oakland tracks because every single line converges into that area. Those are the high priority tracks that are getting replaced first," said Trost.
The other high priority for BART is the major retrofitting the BART tube under the Bay. Currently the tube can handle most earthquakes as is, without major damage. But this multiyear retrofit will enable the tubes to withstand even the mega quakes, the kind expected only once in a thousand years, but capable of being delivered by either the close by San Andreas or Hayward Faults.