Workers tie rebar cage on a part of the high-speed rail system construction already underway elsewhere in California.

A bullet-train route linking Bakersfield with the Antelope Valley received state-level environmental clearance Thursday, allowing pre-construction activity to begin soon if money becomes available.

The California High-Speed Rail Authority board voted to approve the environmental review of building an alignment that would run about 80 miles from F Street and Golden State Avenue in Bakersfield to Palmdale.

The route, mostly following Highway 58, is particularly significant because its construction would close a gap in passenger rail service between Bakersfield and Los Angeles.

"Today's approval represents another major milestone … as we move the project into Los Angeles County," rail authority CEO Brian Kelly said in a news release.

The release said Thursday's action reaffirms the agency's commitment to reaching the environmental process for the project's first phase, from the Bay Area to Los Angeles, by 2023.

Plans call for the route to be built on raised viaducts through most of Bakersfield then drop to surface level through the Edison area. It would run underground through parts of the Tehachapi Mountains, and in some places it would be built at ground level, and on viaducts elsewhere. Through the Antelope Valley it would proceed mostly along the surface.

Environmental advocates have continued to oppose the project because of its potential impacts on threatened plants and animals. But no longer is the project opposed by the city of Tehachapi.

At the request of city officials, the rail authority introduced two sections of sound walls, one in the Ash Village area and one near Arabian Estates. Additionally, the agency agreed to lower the bullet train route's height profile through the Tehachapi area, and it promised to make room for a station that might one day be built in the city.

A representative of the Center for Biological Diversity said mitigation proposed by the rail authority to cushion the route's environmental impacts "does not come close" to minimizing harm to mountain lions and a loss of wildlife connectivity because of the project.

Tiffany Yap, a senior scientist at the CBD, said by email only 39 wildlife crossings are proposed across more than 55 miles of at-grade railroad tracks, "most of which are too small for mountain lions, while others include roads that would deter animals from using them."

"Californians need climate-wise transportation options like high-speed rail, but it shouldn’t come at the expense of sensitive species of animals and plants,” she stated, adding that the route's environmental review does not adequately account for impacts to the western Joshua tree.

Project construction continues along 119 miles of the Central Valley at 35 different sites, with an average of 1,100 workers daily, according to the rail authority.

It estimates the route will become operational in 2033 as part of the start of service between San Francisco and L.A. That's about three years after it expects trains traveling up to 220 mph will connect Merced and Bakersfield.