Union Pacific struggles to get on track.

The maze of rail tracks through an industrial stretch a few miles from downtown Los Angeles is part of a transportation labyrinth that keeps the area's economy moving each day. It's also proven vulnerable both to natural and man-made disaster.

Lost amid the tragedy of last week's collision of two Metrolink trains that killed 11 and injured nearly 200 were the new complications for Union Pacific Corp., which scrambled to find alternate routes after a line running from the rail yards east of Los Angeles to Oakland had to be closed once again.

That line was shut down earlier in the month due to the heavy rains and re-opened on a limited basis two days before the crash.

It was just the latest headache for Omaha, Neb.-based Union Pacific, which carries a third of the nation's freight traffic. Well before this month's incidents, the company has been struggling with crew shortages and ongoing delays out of Los Angeles that have made rail service uncertain at best.

Last week, Union Pacific said that service disruptions in Southern California and Nevada could cost more than $200 million.

The disclosure was made as Union Pacific reported an 76 percent drop in fourth-quarter profits. "The year is off to a difficult start," Chief Executive Richard Davidson acknowledged in a statement.

More broadly, the storm damage and the train catastrophe were reminders that portions of Southern California's complicated transportation network, congested but reliable day-in and day-out, can be taken down by the right set of circumstances.

In the case of both the rains and the train crash, much of the system remained operating as usual--a point some officials said illustrated how the region is not overly reliant on any one route or transportation mode. Buses, for example, were quickly employed to ferry train passengers, and the closed rail lines involve north-south routes that aren't as critical as the major east-west lines.

"If it's the track going to Oakland, that's not the track that most of our goods move on," said Peter Mandia, director of administration for the Alameda Corridor Transportation Authority. "(So) at this time we are not aware it will have any impact on us."

A better way?

But Union Pacific, which uses the Metrolink commuter tracks from its rail yards to Lancaster and Moorpark, has had to hold some northbound trains and detour others on company-owned tracks through the Central Valley and onto Sacramento before heading west to Oakland.

The process will delay delivery of the cargo by as much as a day, depending on the priority placed on the train, said John Bromley, a company spokesman.

"Both those lines are light-freight lines," he said. "They are not our primary routes. (But) that's our access through Santa Barbara and also Saugus and Palmdale and through the Central Valley."

The question likely to be considered in the days ahead is whether the system can be improved. Is it wise, for example, to have so many rail crossings unattended or to have freight trains operating on commuter tracks?

"There is an additional complexity in managing trains carrying people and trains carrying freight on the same right of way," said Jim Moore, chairman of the Daniel J. Epstein Department of Industrial and Systems Engineering at USC. "There are different kinds of scheduling requirements for the two activities. That requires coordination."

Last week, Los Angeles Mayor James Hahn urged the Metropolitan Transit Authority to examine its rail lines to determine if additional safety measures are needed. He also urged the board to seek increased federal funding for safer railroad crossings.

As of late last week, Metrolink was scheduled to allow freight train traffic to move through the crash site beginning on Jan. 28, while its own commuter trains were expected to resume service on Jan. 31.

Law enforcement officials quickly concluded that the collision was not terrorist related, but civil engineers said the incident exposes vulnerability to such an attack. "The problems with these tracks are they are so accessible because they are designed for freight service," said Moore. "There is a real opportunity here for disrupting that system, if that is your objective."

Transportation juggernaut

It's a far different world from the days of General Phineas Banning, who in 1869 built the first rail line in Los Angeles linking the harbor and downtown. Banning was pushed aside by owners of the Southern Pacific Railway, which added Los Angeles to its growing route at a cost of $600,000.

SP partner Charles Crocker reminded city leaders of the consequences if they failed to cooperate. "I will make grass grow in your streets," he said. The first rail line from Los Angeles to San Francisco was completed in 1876 when a gold spike was driven into the final railroad tie in the Santa Clarita Valley.

Over the ensuing decades, Southern California has become a transportation juggernaut in which rail traffic becomes the critical centerpiece. Much of that activity is the result of the Ports of Los Angeles and Long Beach, which in 2003 took in 164 million tons of cargo, the most of any port in the United States. Union Pacific and rival Burlington Northern Santa Fe Corp. handle a third of all cargo moved through the ports.

When it works properly--and it does most of the time--the logistics and transportation network is a marvel of technology and coordination. From the docks, many of the rail cars are moved through the Alameda Corridor, connecting the ports to rail yards east of downtown, where the cars are then mixed and matched for appropriate destinations east and north of the city.

But as evidenced by last week's train crash, there are weak links in the chain.

Authorities said that Juan Manuel Alvarez, apparently planning to take his own life, jumped out of an SUV at the last minute before it was hit by one of the Metrolink commuter trains at the intersection of San Fernando Road and Chevy Chase Boulevard.

That set off a chain reaction in which one of the commuter trains derailed and smashed into the Union Pacific locomotive just before the second Metrolink was hit. Union Pacific's locomotive and the six boxcars were parked overnight on a side track when the collision occurred.

In the hours after the incident, local officials and others expressed concern that a single troubled individual can wreak such personal and economic havoc on the community without any apparent interference.

"This is a complete outrage," said Los Angeles Sheriff Lee Baca said at a news conference. "That an individual would deliberately put their car on tracks, cause a train derailment, affect the lives of hundreds of people and, in effect, kill people, this is a tragedy we will certainly mourn."

But as with concerns about terrorist attacks, finding ways to avert these disastrous events may prove too costly or impractical.

"If it's a suicide thing, I really don't know how you could stop it," said USC engineering professor Najmedin Meshkati. "A suicide attempt is very much like a terrorist attempt. We are very vulnerable to this type of accident until we fix our grade-crossing safety problem."

A grade-separation that would separate the road from the tracks would be ideal, Meshkati added, but it is cost-prohibitive. Certain improvements are possible to avoid accidents, such as a collision avoidance system, advanced warning system and even global positioning systems.

Staff reporter Rebecca Flass contributed to this story.