The California High Speed Rail Authority (CHSRA) surprised local communities on Wednesday by proposing a controversial Burbank-to-Palmdale route featuring above-ground tracks.

The Los Angeles Times reported that the proposed 38-mile track alignment will cross the San Gabriel Mountains via a series of at grade sections and five separate tunnels.

The bullet train’s original route, offered in support of the SB 1856 bond measure passed by the California Legislature in 2000, proposed to follow the Interstate 5 Freeway and tunnel under the 4,144 ft-Tejon Pass to link Los Angeles and Bakersfield.

But due to the supposedly much higher cost, the project’s 2016 Business Plan envisioned the routing to take a 45-mile detour inland through Santa Clarita to Palmdale and on to Mojave. CHSRA would then cross the much lower 3,771 ft. Tehachapi Pass and follow California Route 58 to Bakersfield.

The 2016 Plan projected that the newly proposed route would have the Bakersfield-to-Palmdale “Environmental Schedule Record of Decision” in place by 2017. Emphasizing the importance of gaining environmental clearance to become “shovel ready,” CHSRA claimed to be working with partner agencies, corridor cities, stakeholders, and community members as “part of a comprehensive, ongoing outreach program that incorporates public input and feedback as the program is being developed.”

But the release of CHSRA’s new plan generated a firestorm of protest from several local communities that have demanded since the release of the 2016 Business Plan that the tracks from Burbank to Palmdale be underground.

Santa Clarita Councilwoman and Mayor Pro Tem Marsha McLean told the Times that the city had been warning CHSR it would oppose any route not underground near homes, schools, and churches. She complained that the proposed maps presented on Wednesday do not show enough detail to judge neighborhood impacts but do appear to show there will be ground-level tracts near a business district, hospital, and high school.

The excavation industry’s “Tunnel Talk USA” website analyzed the viability of CHSRA’s three alternative track alignments for a Palmdale-to-Burbank route through the San Gabriel Mountains involving up to seven tunnels “ranging in length individually from several thousand feet to more than 20 miles.”

According to industry experts, each of the alignments will tunnel through “very strong granitic and gneissic rocks to weak alluvial soils,” cross three tectonic faults, and be subject to high groundwater inflows “creating significant tunnel instability or unacceptable environmental impacts.”

The Times reported that CHSRA chose the route alignment proposed on Wednesday because it would be the “easiest to build and cause the least harm.” But officials expect the decision will continue to be controversial because of its potential impacts on businesses, hospitals, schools, residences, ranches and the Angeles National Forest.