California's I-5: A faster, cheaper high speed rail route?

SACRAMENTO — The Grapevine, once considered a prospective high-speed rail route between the San Joaquin Valley and the Los Angeles Basin over the Tehachapi Mountains but disregarded several years ago, could be destined for a comeback.

A three-member operations committee of the California High Speed Rail Authority voted Wednesday to recommend reopening a study of the Interstate 5 corridor through the Tejon Pass. The authority's full nine-member board will consider the recommendation today.

The desire to re-evaluate the Grapevine comes as planners face higher costs and more complicated engineering than originally forecast for two alternatives that thread southeast from Bakersfield through Mojave, Lancaster and Palmdale before making their way into Los Angeles.

Originally, engineers believed they would only need to build 13 miles of tunnels between Palmdale and Sylmar, at the northern end of the San Fernando Valley, said Andrew Althorp, a regional project manager for Parsons Brinckerhoff, a consulting firm working for the rail authority. But more detailed studies since 2005, Althorp said, have given planners a better understanding of seismic concerns and the construction needs involved to avoid earthquake faults as well as increasing development along the routes. Althorp said engineers now believe they will need to bore at least 28 miles of tunnels.

A route over the Grapevine would be about 25 miles shorter than the roundabout Lancaster/Palmdale route. It could shave nine to 10 minutes off the time it takes a high-speed train to get from Bakersfield to Los Angeles.

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