A new Caltrain study shows that its trains can share the same track with a high-speed rail line, agency officials said Wednesday, an outcome that would address Peninsula residents' and lawmakers' concerns about the impact of building new tracks through their neighborhoods.

Six electric commuter trains and four bullet trains shuttled per hour between the Hayward Park station in San Mateo and the Redwood City station on a blended track in a computer simulation created by LTK Engineering Services. The mock-up assumed such variables as an electrified track, an advanced signaling system and a new set of passing tracks, none of which currently exist. The cost of the signaling system alone is roughly estimated at $250 million.

"It's a significant development," Caltrain spokesman Seamus Murphy of the analysis. "A lot of people have major concerns about the cost of the (high-speed rail) project and its impact on communities. This answer is encouraging, because it shows we do not have to build a separate track."

The idea of a "blended" rail system was proposed in April by state Sen. Joe Simitian, U.S. Rep. Anna Eshoo and state Assemblyman Rich Gordon. The proposal was meant to alleviate the concerns of Peninsula residents about what will happen in their areas if a second set of tracks is built as planned to accommodate the high-speed trains. As it stands, the project involves building such tracks, which could wipe out nearby buildings and disrupt traffic patterns.

The blended system could still involve building extra tracks. Under one scenario advanced by Caltrain, a 7- to 8-mile four-track section would be built near the middle of the Peninsula line.

This would enable the bullet trains to pass Caltrain's commuter trains, allowing the faster trains to maintain their speeds.

The survey released Wednesday is still in the preliminary stages.

There will be a second set of findings followed by a draft analysis, according to Miriam Lee, the acting director of Caltrain's modernization program.

A transportation activist expressed guarded optimism about the survey.

"There are many ways to skin a cat, and hopefully we're getting to something that does work," said Elizabeth Alexis, co-founder of Palo Alto-based Californians Advocating Responsible Rail Design. "The devil is in the details. We really have to look at the details and understand all the implications."

"This is the beginning, not the end, of an interesting conversation," she added.

plan to build high-speed rail
In April, state Sen. Joe Simitian, U.S. Rep. Anna Eshoo and state Assemblyman Rick Gordon suggested a "blended" high-speed rail system. The plan was studied for the agency:
$250 million
Estimated cost of advanced signaling system slated for high-speed rail line currently being studied by Caltrain