While stressing the preliminary nature of the study results, Marian Lee, the acting director of the Caltrain Modernization Program, said the possibility clearly exists for a "blended system" that could accommodate high-speed trains and a modernized Caltrain along a shared two-track corridor.
"The blended track system has merit," she said.
The study, conducted by LTK Engineering Services using computer simulations, concluded that if Caltrain were to electrify all of its operating trains, upgrade its signal system, and construct a 7- to 8-mile stretch of "passing tracks" in the middle section of the line, the existing two-track right-of-way could accommodate up to four high-speed trains and six Caltrain trains per hour.
The analysis supported a concept proposed by Peninsula lawmakers Rep. Anna Eshoo, D-Menlo Park, state Sen. Joe Simitian, D-Palo Alto, and Assemblyman Richard Gordon, D-Menlo Park, who in April called upon the California High-Speed Rail Authority to revisit its plans to build out a high-speed rail system that would run separately from Caltrain between San Francisco and San Jose.
A high-speed rail system running independently from Caltrain would be duplicative and would never earn local support, the lawmakers said in a joint statement issued two months ago.
Sen. Simitian said Aug. 17 that he welcomed the results of Caltrain's test study.
"My colleagues and I have been making the case that High Speed Rail 'done right' means a 'blended system' along the San Jose to San Francisco corridor — a system that integrates High Speed Rail with a 21st century Caltrain," Simitian said in a statement.
Since California voters approved Proposition 1A in 2008, which authorized $9.95 billion for the high-speed rail system, Peninsula residents and officials have vociferously debated the merits of the rail plans, including design options that entailed adding aerial tracks and tunneling underground.
Ms. Lee cautioned against overplaying the results of the analysis, emphasizing that much more research would need to done before plans to construct a blended system could move forward.
"This is an ongoing study," she said. "There are a lot of assumptions we still have to think through."
She said the test did not consider freight train use along the corridor, the impact to cities like Belmont where passing tracks would be installed, or the need to accommodate increased train traffic by lowering crossing gates and blocking street traffic at more than 50 intersections between San Francisco and San Jose.
The California High-Speed Rail Authority CEO Roelof van Ark emphasized in a statement Aug. 17 that the shared-track plan would be an "initial" step for the bullet-train system, which eventually would call for four tracks and the ability to run 10 to 12 trains per hour.
The two-track plan would "allow us to provide a reduced but adequate initial level of high-speed service in the near term," he said.
"I look forward to working closely with our planning partners along the corridor to evaluate this provisional study and pursuing a regional consensus to advance this segment," Mr. van Ark said.
Rep. Eshoo said she was "pleased" with the findings but that more work needs to be done in order to reach a consensus.
"The preliminary analysis shows a viable path forward that minimizes community impacts by keeping the project substantially within the existing Caltrain right-of-way, avoids unwanted aerial viaducts, and saves taxpayers billions of dollars," she said.
The cost of the high-speed rail system, which is planned to stretch from Los Angeles to San Francisco, was recently estimated at $67 billion.
Caltrain has scheduled an outreach meeting on Friday, Sept. 2, with the Peninsula Cities Consortium.