Beleaguered MTA on Verge of Tunnel Triumph

Hundreds of feet beneath the Santa Monica Mountains, far below a residential driveway, Los Angeles will mark a milestone today, when a massive tunneling machine punches through a wall of rock and soil and opens a path for the subway between the San Fernando Valley and Hollywood.

But unlike similar occasions--the opening of the Los Angeles Aqueduct or construction of the Pasadena Freeway, the city’s first--it will be a celebration marked not by a sense of promise, but by a realization of limitations.

When the mechanical mole claws through the final feet of its almost 2.4-mile subterranean journey, a city famous for its love affair with the car will have a 17.4-mile subway tunnel from downtown Los Angeles to North Hollywood. That task probably was the system’s greatest engineering challenge. But the achievement is overshadowed by growing apprehension that it marks not the end of the beginning for Metro Rail, but the beginning of the end.

By the time the subway line from Union Station to North Hollywood actually opens in the first spring of the next century, local, state and federal taxpayers will have spent at least $4.5 billion on the mass transit system, more than $250 million a mile. And chances are none of the planned extensions will be built in the foreseeable future.

To historian Kevin Starr, that is an anxious prospect. “Having invested in a public works of this sort, there has to be a lot of thought about walking away from the project,” he said.

Something like such a retreat, however, appears increasingly likely.

With an absence of political consensus and a hard reality that the money may not be available, visions of a vast subway network--to the Eastside, Mid-City and across the Valley are fading fast.

And in a quirk of timing, this subway tunnel to the San Fernando Valley comes as the Valley talks of secession from Los Angeles.

“There is a delicious irony that just as we build transportation linkages to the Valley, the Valley wants to say goodbye to the city,” observed UC San Diego political scientist Steven Erie.

Like the active earthquake fault that the tunnel crosses, the fracturing of the subway’s political support will be lurking beneath the surface, as politicians and construction workers gather this morning to celebrate the completion of the first of the twin tunnels through the mountains.

“It’s a triumph of man over geology,” said an engineer involved in carving the tunnels between the Valley and Hollywood.

Charles Stark, construction chief for the Metropolitan Transportation Authority, called the cross-mountain project “the toughest and most challenging” phase of the decade-old subway project.

The geological conditions encountered by miners working the tunnel boring machine ranged from “very hard granite-like rock to hard basalt and less hard shales and sandstones,” said Harvey W. Parker, a Seattle-based geotechnical and tunnel engineering consultant. “It’s a very difficult challenge in engineering terms and construction terms.”

Parker, a member of the MTA’s tunnel advisory panel, said a significant achievement was using mining techniques to carve out a wider tunnel through the active Hollywood Fault zone, where the rock is even more fractured than along the rest of the route. The extra width is intended to provide the ability for the tunnel to flex in an earthquake.

But for the workers involved, the tunnel breakthrough is bittersweet not only because of the recent death of a construction colleague in Universal City, but also because the injury rate on the project was significantly higher than the national average.

And the MTA’s cross-mountain tunnel contract with Traylor Brothers/Frontier-Kemper is behind schedule and running $41 million over the original $124-million budget.

The digging--which began in May 1996 and involved 150 workers--was painfully slow at times and stopped altogether for six weeks last year when one of the two digging machines--nicknamed Thelma and Louise by workers--got stuck. The machines began their journey in Universal City, in a deep shaft across from Universal Studios. Hanging over the entrance to the twin tunnels is a sign reading: “Hollywood 2 1/2 miles”

Except for workers unloading the “muck boxes” filled with dirt and rock, there was little activity Tuesday around that pit, since the miners were deep in the tunnel, approaching the La Brea Avenue shaft near Hollywood Boulevard.

Inside the dimly lit tunnels, the ground is muddy from water seeping in--some of it dripping from above. An odor permeates the tunnel--from the use of 550,000 pounds of chemical and concrete grouting to reduce water intrusion, said a subway construction supervisor.

Workers must wear high boots, orange vests, goggles, hard hats and carry an emergency breathing apparatus and a flashlight.

At the tunnel face, the huge digging machine--as long as a football field--is operated by a crew of about half a dozen workers.

On the side of the tunnels, the dirt and rock is still visible--it will be covered later by a concrete liner. Curved steel ribs provide support every four feet. In all, workers have installed 10.2 million pounds of steel to support the tunnel walls.

A temporary track allows trains to haul out dirt and rocks in “muck boxes,” which are then lifted out of the pit, their contents emptied and trucked to landfills. Pointing to the enormity of the task, John Townsend, resident engineer for construction manager JMA, noted that it took a five-car train (each car is as big as dump truck) to carry the dirt and rock from just four feet of tunneling. It took about 35,700 truckloads to haul away the 312,000 cubic yards of dirt and rock carved out by the tunnel boring machines.

Nearly 275 million gallons of water have been pumped out of the tunnels, draining springs that have long fed surface streams in the mountain canyons high above.

While MTA officials and their contractor await the breakthrough in the first tunnel, the other machine digging the second tunnel lags more than 470 feet behind. It will not break through to Hollywood for several weeks. Then, the tunneling will be complete. But much work lies ahead, including the use of explosives to blast through rock to create storage rooms and cross passages where trains traveling in opposite directions can switch tracks.

A huge concrete liner, tracks and electric third-rail must be installed before the Hollywood to North Hollywood segment can open, now scheduled for May 2000.

Currently, only 6 1/2 miles of the subway is in operation from Union Station to Wilshire Boulevard and Western Avenue. The Red Line carries just under 40,000 riders a day. An extension from Wilshire and Vermont to Hollywood and Vine is scheduled to open in December of next year carrying, with it MTA’s hopes for increased ridership.

When the final leg is open, the county transit agency plans to reroute buses in the Valley to connect with the subway.

Unlike previous segments of the subway that were built through loose sedimentary ground, the tunnels from Universal City to Hollywood passed through six distinct geological formations and the Hollywood Fault in traversing the Santa Monicas.

They are by far the deepest tunnels on the subway system, ranging from 165 feet below ground to 900 feet underneath the tallest peak in this part of the mountain range.

The tunnel breakthrough will occur 250 feet under private property in the Hollywood Hills--a little bit north of the driveway leading to the home at 2005 La Brea Terrace.

Some of the residents knew that the subway was under construction but were unaware of their moment of glory.

“Is that right?” said Michael McLean, an elementary school music teacher who lives in the house. “That is interesting.”

Toby Wightman, president of the American Underground Construction Assn. and an engineer with Kiewit Construction Co. in Omaha, said that “holing through,” as the breakthrough is called in the industry, is a big event for tunneling crews.

“It means ‘Thank God, it’s over.’ ”

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

Break-On Through

The first of two Metro Rail subway tunnels through the hard granite and softer shales deep inside the Santa Monica Mountains will link Hollywood and the San Fernando Valley. A giant tunneling machine that began its underground mining in North Hollywood almost a year and a half ago is expected to slice through the final feet of rock and soil today to link up with a subway tunnel from downtown Los Angeles.

Metro Red Line

Union Station to North Hollywood: 17.4 miles

Revised budget: $4.5 billion

Spent to date: $3.5 billion

In operation: Union Station to Wilshire/Western: 6.5 miles

Coming Attractions: Wilshire/Vermont to Hollywood/Vine opens December 1998; Hollywood to North Hollywood opens May 2000

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The Boring Work

Two tunneling machines, nicknamed Thelma and Louise, are chewing through the mountain range. Thelma, in the east tunnel, dug through 64 feet of rock between Monday and Tuesday mornings. Louise, stalled in the west tunnel, is about 500 feet behind.

* Crossover tracks: These let trains change direction by switching tracks. They will be built later.

* Twin tunnels: Two 20-foot, eight-inch diameter tubes run parallel, 77 feet apart.

* Crossing the fault: When the tunnel crosses the Hollywood Fault zone it will be even wider to accommodate movement in a major earthquake. The tunnel here is 29 feet, 6 inches in diameter, 27 feet 6 inches when lined with concrete.

* Slow going: The nearly vertical layers of rock types presented tough challenges, ranging from very hard granitic rock to softer sandstone and shales.

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Tunnel Facts

Total length: 12,585 feet; nearly 2.4 miles

Maximum depth below surface: 900 feet

Minimum depth below surface: 165 feet

Work began: May 10, 1996

Excavated: 35,700 truckloads of dirt and rock

Water pumped out: 300 million gallons

Steel installed: 10.2 million pounds

Seismic issues: Crosses Hollywood Fault

Diameter of tunnel: 20 feet, 8 when dug; 17 feet, 10 inches with a concrete liner in place

Researched by JEFFREY L. RABIN / Los Angeles Times