A tunnel under the San Gabriel Mountains has been added as an alternate route for the $67.6 billion San Francisco-to-Los Angeles high-speed rail train’s Southern California segment connecting Palmdale to Burbank, officials said Monday. The new, more direct corridor, along with the S-shaped alignment proposed in 2007 that roughly follows the 14 Freeway through Santa Clarita, both will be discussed at seven upcoming public meetings of the California High-Speed Rail Authority in Los Angeles County beginning next week.

A tunneling option that runs in a straight line from the Palmdale Transportation Center directly to a station at the Burbank airport is being considered by the CHSRA for the first time as part of its environmental review, said Michele Boehm, CHSRA Southern California Regional Director.

“Yes, we have included it as a corridor to look at in the next phase of the analysis,” Boehm said on Monday.

The tunnel route will be shorter than the 60-mile-segment route released in 2007, she said, although she did not know exactly how much shorter. Boehm said the alternative would shave time off the trip from San Francisco to Los Angeles. The CHSRA is also studying the route for a second and final Southern California segment from Burbank to Union Station in downtown Los Angeles.

A high-speed rail train would run from San Francisco to Los Angeles in a little under three hours at speeds as high as 220 mph, according to the CHSRA. The controversial project approved by voters through a 2008 $9-billion bond measure received a boost from Gov. Jerry Brown earlier this month when he said he would put aside 25 percent of the state’s revenues from its cap-and-trade program.

The Legislative Analyst’s Office says that could amount to $2 billion a year, something Boehm said she could not speculate on.

The tunneling route under the San Gabriels is supported by Supervisor Michael Antonovich, who wrote a letter to the agency in October suggesting the route after hearing a lot of negatives from the cities of Acton and Santa Clarita over the first route.

“It is a promising alternative,” said Michael Cano, Antonovich’s transportation deputy. “The supervisor is pleased with the response from the Authority.”

Santa Clarita Mayor Pro-Tem Marsha McLean agrees with Antonovich. The city is in support of the tunnel proposal which would not go through Santa Clarita. The alignment that parallels the 14 Freeway would take out homes, churches and bring the speeding train dangerously close to two schools in the city, she said.

“This tunnel is just as feasible and has far less impacts to us and the folks down the line. It just makes sense,” McLean said.

The scoping study will look at the feasibility and cost estimates of tunneling under the San Gabriel Mountains, Boehm said. She added: “These types of tunnels are being built in other parts of the world. It would be appropriate for us to study it for this location.”

The public meetings will be held from 5:30 p.m. to 7:30 p.m. Aug. 5 to Aug. 19 in the following locations:

Aug. 5, William S. Hart Regional Park, 24151 Newhall Ave., Newhall.

Aug. 6, Buena Vista Branch Library, 300 N. Buena Vista St., Burbank.

Aug. 7, Chimbole Cultural Center, 38350 Sierra Highway, Palmdale.

Aug. 11, Acton-Agua Dulce Library, 33792 Crown Valley Road, Acton.

Aug. 12, Sylmar Public Library, 14561 Polk St., Sylmar.

Aug. 14, Lake View Terrace Recreation Center, 11075 Foothill Blvd., Lake View Terrace.

Aug. 19, Los Angeles Union Station, Fred Harvey Room, 800 N. Alameda St. Los Angeles.

The project was held up in November by a judge who ruled the agency had not complied with the ballot measure that voters approved. The state appealed the ruling and a decision is expected in late August, said H.D. Palmer, a spokesman for the state Department of Finance.

While the project still has a substantial funding gap, the rail authority’s CEO Jeff Morales said he is courting private backers to help make up the difference.

Earlier in the month, the CHSRA began demolition of structures to pave the way on a 29-mile stretch of track near Fresno. The portion of the line will run about 130 miles and connect Madera to Bakersfield.

With extra funding from polluters that contribute to the cap-and-trade fund and expediting environmental reviews, the Palmdale-to-Burbank segment could be completed in 2022, sooner than the original end date of 2029, said Adeline Yee, a spokesperson for the CHSRA.

— Jessica Calefati of the Bay Area News Group contributed to this article.