The California High-Speed Rail Authority has received a special use permit to conduct boring samples in the Angeles National Forest where it proposes to put tunnels for its rail project between Palmdale and Burbank.

The U.S. Forest Service notified the authority Dec. 1 that it can do an investigation in the forest in five preferred and three alternate spots to determine the subsurface composition and geologic and seismic makeup of the mountains.

“The results of this testing will provide data that the team will use to evaluate the range of alignments that are proposed under the San Gabriel Mountains,” the authority said.

The authority has six routes under consideration that would require tunneling beneath the national forest and San Gabriel Mountains National Monument. The six alternatives would have the trains exit the mountains in one of three locations: Lakeview Terrace; just south of the 5 Freeway; or at Montague Street and San Fernando Road in Pacoima.

Depending on the exact alignment, the mountain tunnel routes would displace between 16 and 93 single-family homes, up to 26 multifamily complexes, 77 to 94 commercial buildings and 65 to 107 industrial buildings,

The tunneling proposal has generated strong opposition from residents and property groups in the east Valley, including the Foothill Trails District Neighborhood Council and Shadow Hills Property Owners Association.

The authority also has under consideration four routes that would run roughly parallel to the 14 Freeway. Even those alternatives would require extensive tunneling as they pass through the narrow freeway corridor that connects the Santa Clarita Valley to the Antelope Valley.

The authority plans to have a draft environmental impact report on all the routes completed by the end of next year or early 2017, with the final report ready by the end of 2017.

The Palmdale-Burbank section is just one segment of the planned 700-mile, $68 billion high-speed rail project that would connect Los Angeles and San Francisco by 2029.