Ross Capon's proposal for construction of light rail lines to feed existing Metrorail stations {Letters to the Weekly, Nov. 29} responded to my Nov. 15 letter on the ongoing Prince George's County study of transit alternatives. He makes some excellent points; he introduces the concept of an "express" Metrorail fed by a "local" light rail system. We both seem to agree that the original design basis for Metrorail to provide public transit to as many population centers as possible went awry because the neighborhoods served by Metrorail change drastically as soon Metrorail appears on the scene.

We must recognize that we'll never be able to provide door-to-door Metrorail service for commuters. We'll still need feeder bus lines, cars and possibly light rail to make connections. Therefore, because of the tremendous cost of rail systems, let's (1) build the most expensive portions (heavy rail) in the least expensive way (as short and straight as possible), (2) offer the least disruption to present community life (build along existing commercial or undeveloped routes) and (3) provide easy access to Metro stations, recognizing that of necessity they'll be situated several miles apart (build along or near major highway systems).

It's inevitable that Metrorail will be extended into Prince George's County. When it is, its design should be based on the realization that its location will drive future development. A snapshot of current population distribution is essentially useless, because the moment Metro expansion plans are finalized the picture begins to change. Therefore, our planning should be controlled by what we want the county (and the state) to look like in 20 years, 30 years or even 50 years. What we decide now will forever determine that future. TOM KEEGAN Bowie