Officials Seek Less Disruptive Way to Build Red Line Station

Stung by complaints about torn-up streets during subway construction downtown, Los Angeles transit officials said Monday they are considering alternative station-construction techniques to avoid hard feelings--and lawsuits--as the Metro Red Line is tunneled under Hollywood.

Costs of the various alternatives, including one that would tear up hundreds of feet of Hollywood Boulevard at a time and another that would not disturb any street at all, will be estimated over the next month.

Directors of the Rail Construction Corp., the subway-building subsidiary of the Los Angeles County Transportation Commission, could choose among the alternatives before Thanksgiving, but no decision date was set.

In presenting several alternatives to RCC directors Monday, staff engineers and consultants appeared to favor a “hybrid” technique that would reduce the need to tear up busy streets for a period of months.

Board member James T. Pott urged staffers to carefully consider the costs and inconvenience that method would inflict on merchants and commuters when they compare it to another, costlier proposal to tunnel out the stations without tearing up any streets.

Hollywood merchants have been vocally anxious about what Metro Red Line construction might do to their efforts to revitalize that historic district. Closing down or narrowing Hollywood Boulevard and cutting off cross streets could kill revitalization, they fear.

In response, the RCC began exploring options to traditional “cut and cover” construction. After rejecting such other, exotic-sounding options as “jacked pipe arch” as impractical or inappropriate, they proposed two alternatives: tunneling, or “mining,” stations, or using a “hybrid” of mining and cut-and-cover.

In cut-and-cover, about 600 feet of a street is “cut,” or dug out to a depth of 40 feet, and part of the hole is temporarily “covered” to let a trickle of traffic pass while a station is built. Eventually, the finished structure is buried and the street rebuilt.

The tunneling option, known as the New Austrian Tunneling Method, calls for widening the tunnels through which the trains will run between stations. Under this method, which does not tear up the street, the tunnels would be widened a few feet at a time where stations would be placed. The widened part would then be sprayed with a concrete liner to prevent collapse until permanent walls and ceiling are built.

Engineers said this method would need stations hundreds of feet longer than cut-and-cover construction because train-control and power-supply equipment would have to be put at either end.

When a station is built in a vertical hole in the street--the more conventional method--train controls and electrical equipment can be installed above the station ceiling. But that is impractical in a tunnel, they said.

The hybrid option would tunnel out the middle of the station, where passenger platforms are located, but would cut-and-cover the ends of the station, where train controls electrical equipment are housed. This method would limit disruptions to a 100-foot section at one end and a 160-foot section at the other.

RCC President Edward McSpedon said the hybrid method would reduce street disruptions and avoid blocking cross-traffic without the high cost of tunneling.