Some of the longest rail tunnels in North America would be used to bring California’s high-speed rail tracks from Northern California into the San Fernando Valley, under the latest plan to go before officials on Tuesday.

But the rail line would remain above ground in most of Los Angeles, under the new plan.

The California High-Speed Rail Authority will review the plans at a meeting Tuesday in Anaheim. Construction has already started near Fresno on the first tracks, but funding has not been found for most of the $68 billion project, now on track to be completed in 2025.

Plans to loop the tracks around mountains from Palmdale to Santa Clarita, and then use the existing rail corridor along San Fernando Road to Los Angeles, have been dropped.

Instead, engineers propose to bore tunnels under the mountains at the northeast end of the San Fernando Valley, and drill tunnels as long as 14 miles from Acton to the San Fernando Valley. There would also be bridges and an additional 10 miles of shorter tunnels along the 14 Freeway near Palmdale.

Three tunnel alignments are envisioned, and all three may affect rural neighborhoods at the eastern end of the San Fernando Valley, the state agency said.

The northernmost route, called SR14 because it would parallel the 14 Freeway in Acton, would have 21,717 houses within 300 feet of the center of the above-ground tracks. The other two alignments are called E1 and E2, and have longer tunnels: 22,232 homes would be close to E1, and 14,328 close to E2.

In Burbank, the plan calls for a new high-speed rail station to be built near Bob Hope International Airport, at Hollywood Way. The high-speed tracks would be laid on existing rail property west of the tracks shared by Amtrak, Metrolink and Union Pacific freight trains, from the airport as far south as the 2 Freeway bridges.

There, Metrolink trains would use a new flyover to “blend” in with the high-speed trains, all the combined line could cross the L.A. River on a new bridge near Figueroa Street to arrive at Union Station without using elevated track structures.

A set of proposed tunnels near Dodger Stadium have been rejected, as they would have cost an estimated $260 million per mile and brought trains out in residential neighborhoods in the Frogtown area.

The revised plan also drops plans for a viaduct along Main Street near Chinatown to carry high-speed trains to Union Station, which the agency said would be too noisy for residents.

The agency notes there had been talk of an elevated high-speed tracks above Union Station, but said this week that Metro has plans now for a new “flow through” tracks at Union Station and over the 101 Freeway, to handle high-speed and Metrolink/Amtrak service to the south and east.

The shared-use tracks would affect 42 industrial or commercial properties in the area of San Fernando Road, as flyover overpasses would need t be built to blend high-speed trains and current passenger operations. In addition, some maintenance operations would have to be removed from the relatively-new Metrolink maintenance yard north of the 110 Freeway.

For the future leg of high-speed rail, from Union Station to Anaheim, planners proposed a joint set of Metrolink, Amtrak and high-speed tracks along the current rail alignment, with tunnels proposed under residential neighborhoods in Fullerton.

Stations are proposed for Norwalk and Fullerton, and that line would connect the statewide system from Los Angeles to the futuristic new Anaheim Regional Transit Interconnection Center, near Anaheim Stadium.

No significant plans have been released yet for the branch of high speed tracks east from Los Angeles through the Inland Empire, and south from there to San Diego.

Staff will provide the state’s High Speed Rail Commission with an update on all this at 9:30 a.m. Tuesday at Arena Room 1 of the Anaheim Convention Center, near Disneyland.