BART spokesman Linton Johnson said directors approved the $403,563 contract with the King-American Ambulance Company in San Francisco because a pilot program that's been in place since last October has resulted in a 68 percent drop in medically-related delays at the four stations.
The stations are the Embarcadero, Montgomery, Powell and Civic Center stations.
"The money is well worth the investment so that we can keep our trains on time as much as possible," Johnson said.
A similar pilot program at the West Oakland station has led to a 95 percent drop in medically-related delays there, he said.
Johnson said that before the pilot program was started, trains at stations where passengers suffered medical problems during rush hour were often delayed between 5 and 15 minutes while transit officials waited for paramedics from local fire departments or other agencies to arrive at the scene.
He said having paramedics at or near busy stations during commute hours means that they can respond to medical problems within a few minutes or even within seconds.
Johnson said there aren't medical problems at BART stations every day but such problems occur often enough to be an issue.
