Transit Update : Decision Time: The fate and scope of a rail line in the Valley probably will be decided in March.

After more than three years of seemingly endless debate over where and what kind of mass transit line to build in the San Fernando Valley, the time for decision is almost at hand.

Recently, the Los Angeles County Transportation Commission released a voluminous report on alternative rail systems for the Valley.

The commission, which is building a regional network of rail lines using the extra half-cent sales tax that voters approved in 1980, plans to use a $2.1-million Environmental Impact Report as the basis for selecting a route, probably in March.

Throughout the long-running debate, business leaders have argued that an east-west line is essential to keep the Valley from bogging down in congestion as the Ventura Freeway and other cross-Valley arteries stagger under ever-increasing traffic.

Well-organized homeowner group leaders agree that congestion relief is needed, but they contend that no rail line can be allowed to disturb the Valley’s many single-family neighborhoods.

Most homeowner group leaders want a cross-Valley subway with no stations in residential areas.

Business leaders contend that such a system would be too costly and that insisting on a subway at all costs would jettison the Valley’s chances for getting any rail line.

Last summer, the fighting ebbed dramatically with the emergence of a plan to put aside for now any hope of a cross-Valley line.

Instead, available funds would be used to extend the downtown to North Hollywood Metro Rail subway west to the Sepulveda Basin. From there, commuters bound for the West Valley would transfer to express buses.

The plan, drafted by state Sen. Alan Robbins (D-Tarzana) and Los Angeles City Councilman Marvin Braude, has drawn widespread support and is expected to be given strong consideration by the commission. It also was examined in the recently released report.

* The Basics: Some questions and answers on rail systems.

Q. What San Fernando Valley routes were studied?

A. The report examined 10 variations on two basic routes. They are the Southern Pacific railroad freight right-of-way that crosses the Valley from North Hollywood to Warner Center parallel to Chandler and Victory boulevards, and the Ventura Freeway shoulder from Universal City to Warner Center. Along both routes, the commission studied the possibility of stopping the line for now in the Sepulveda Basin.

Q. Besides selecting a route, will the commission make any other decisions affecting the Valley?

A. Commissioners also will have to decide if the line should be a subway, in a shallow or deep trench, at ground level or elevated. Since tunneling costs more than $100 million per mile, the answer to that question will go a long way to determining the cost of the Valley system. The commission also will decide if the line should use light-rail technology similar to that used in the nearly completed Long Beach-Los Angeles line or heavy rail equipment like that of the under-construction Metro Rail subway.

Q. What is the difference between heavy and light rail?

A. Both use the same size track, but heavy-rail systems, such as Metro Rail, use trains of six to nine cars, while light-rail trains seldom exceed three cars. Heavy rail’s greater length sharply increases its carrying capacity. But it also means that heavy-rail stations must be correspondingly long and expensive. In addition, heavy-rail systems get their power from an electrified third rail, which means they must be completely separated from pedestrians and vehicles. Most light-rail lines get their power from an overhead electric line, which means they are cheaper to build and can travel on city streets. Rail experts say that the type of equipment is less important in terms of cost than is the question of whether the line is tunneled or ground level.

Q. Is the Valley guaranteed a rail line?

A. Not at all. The County Transportation Commission, which has the final say on which routes get built, has two other proposed lines studied and ready to go and is scheduled to decide in March which to build. Rival routes are from downtown Los Angeles to Pasadena and from El Segundo north past Los Angeles International Airport to Marina del Rey. The Westside line would be an extension of the Century Freeway light-rail line that eventually will be extended north to Sylmar along the San Diego Freeway corridor. Commissioners acknowledge privately, however, that the Valley has the political clout to get the next rail line provided there is a consensus among local leaders on a preferred route.

Q. Is there enough money available right now to build a Valley rail line?

A. Not to build the kind of system that would avoid vocal opposition. The commission found that the cost for the 10 Valley rail alternatives ranged from $500 million for a ground-level light-rail line between North Hollywood and the Sepulveda Basin to $3.5 billion for a subway from Universal City to Warner Center. The Robbins-Braude plan would cost $1.3 billion, according to the commission’s report. The commission, which has not projected spending beyond 2000, expects to have between $600 million and $800 million available during the 1990s that is not already committed to the three lines under construction--Metro Rail and the Long Beach and Century Freeway light-rail lines. Thus, almost any Valley rail alternative is not likely to be completed until well after 2000.

Q. Is there a possibility of more rail-building money in the 1990s?

A. Yes. County transit officials might place another half-cent sales tax before the voters. If passed by a majority of those voting, such a measure could double or even quadruple--to possibly $500 million a year--the money available to build rail lines. Bond measures also have been proposed as a means of generating more rail-building funds.

Q. What role does the Los Angeles City Council play in route selection?

A. Officially, it has no role. But transit planners say that they would be loath to approve any project that is opposed by the council. One year ago, the council endorsed both routes that were studied in the newly released Environmental Impact Report, leaving it up to the commission to make the final selection.

Q. Why has the Southern Pacific Coast Line been dropped from consideration?

A. The coast line, which crosses the Valley diagonally from Burbank Airport to Chatsworth, seemed to be everyone’s second choice for a cross-Valley mass transit route, but it had no strong proponents. Eventually, it was dropped when rail planners determined that it would be a good candidate for a commuter rail line. It is under study for such a line.

Q. What is commuter rail?

A. Unlike heavy- and light-rail lines, which require their own tracks, commuter lines are merely traditional-style passenger cars pulled by a traditional railroad engine. Because commuter trains are relatively slow and stations usually are far apart, carrying capacity is much less than heavy- and light-rail lines. On the other hand, the cost of starting up a commuter rail line is a fraction of light rail’s cost. Commuter rail is being studied between Oxnard and downtown Los Angeles along the coastline, which would make at least four stops in the Valley in addition to Simi Valley, Moorpark and Camarillo.