OAKLAND — A former BART director sees a tantalizing opportunity to speed up some commutes between San Francisco and communities along Amtrak’s Capitol Corridor.

Bob Allen, the transit system’s District 5 representative from 1974 to 1988, proposes a transfer station at Seventh Street in Oakland where BART’s transbay line crosses over the Union Pacific tracks that carry Amtrak trains.

“From a transfer station there, 16 or more (BART) trains per hour would reach four BART/Muni downtown San Francisco stations in six to 10 minutes,” Allen said.

There already is a BART/Amtrak transfer station in Richmond, but most travelers would save time transferring at Seventh Street Oakland, Allen said. BART makes eight stops and takes 28 minutes between Richmond and West Oakland, which is about three-quarters of a mile from his proposed rail hub at Seventh Street. Moreover, he pointed out, only one in four transbay trains goes via Richmond whereas all would go via Oakland Seventh Street.

Amtrak takes 15 minutes or less from Richmond to Emeryville, which is about two miles from Seventh Street.

Transferring at a Seventh Street rail hub instead of Richmond would reduce travel time between San Francisco and Amtrak’s Capitol Corridor or San Joaquin line by about 13 to 25 minutes and eliminate several station stops, Allen said. And, “with an I-880 interchange there, it would be great for regional and intercity buses also. If a mishap closed either the (Bay) bridge or the tube, this would simplify an intermodal emergency commute operation.”

Another BART-Amtrak transfer opportunity exists at Oakland Coliseum.

Allen said he has suggested a Seventh Street transfer station to BART and the Metropolitan Transportation Commission since about 1990, but the idea didn’t gain traction. Another missed opportunity, he said, was when MTC decided to make its new headquarters at 390 Main St. in San Francisco.

Seventh Street “would have made a beautiful place for MTC to put their headquarters rather than San Francisco, where they’re far from the BART/Muni stations,” Allen said. “And it would tie in with the Capitol Corridor.”

James R. Allison, manager of planning for the Capitol Corridor Joint Powers Authority, said his agency’s recently adopted Vision Plan Update is considering a new connection with BART in the general West Oakland area.

“But where that can or should be would be subject to working with BART and other Bay Area authorities over a 20-plus year time frame,” he said in an email.

Moreover, Allison said, BART trains are already full at peak hours at the existing West Oakland station, so adding a Capitol Corridor there “would not be ideal unless BART capacity would be modifiable somehow.”

BART spokesman James K. Allison, no relation to James R. Allison, said BART has no plans to build a station at Seventh Street, adding, “I am not aware that were any plans, certainly not within the last 10 years.”

Contact Tom Lochner at 510-262-2760. Follow him at Twitter.com/tomlochner.