A decade-old proposal to haul Montgomery County's garbage by rail to West Virginia -- an idea previously derailed by opposition from West Virginia officials -- has been revived in this election year as citizen opposition mounts against a proposed multimillion dollar incinerator.

The idea of hauling the garbage to fill in spent strip mines in West Virginia was all but abandoned by county officials in favor of the costly incinerator project, but it now has backers among politicians, including incumbents, seeking various offices this fall.

The $250 million incinerator, which would open in 1987 if approved, was supposed to be the county's long-term solution to a great dilemma: how to dispose of 1,400 tons of trash -- enough to cover a football field a yard deep -- daily. The incinerator has been backed by consultants hired by the county, and several officials went to Europe last spring to inspect trash-burners there.

But the incinerator idea has drawn fire from a small but vocal citizens group that contends the facility will spew toxic gases into the air while clogging traffic at one of the county's busiest intersections--Rte. 355 and Shady Grove Road in Gaithersburg.

In the face of the citizens' complaints, the County Council, all of whose members are seeking reelection, last week toned down the language of its 10-year solid waste plan. The plan now calls the incinerator just one proposal of several, while leaving open the long-debated possibility of rail haul.

Yesterday, Del. Luiz R. Simmons, a Republican candidate for county executive, told a group of about a dozen citizens opposing the incinerator that if elected, he would not build the incinerator and, instead, would vigorously push the idea of rail-hauling Montgomery's refuse to sites in Grant County, W. Va. He accused incumbent executive Democrat Charles W. Gilchrist and the all-Democratic council of quashing the rail-haul idea before fully exploring it.

Alexander J. Greene, Gilchrist's special assistant who oversees garbage-related issues, responded that the executive is just as committed to rail-haul. He pointed out that Gilchrist only yesterday placed advertisements in some trade journals and local newspapers, asking for "expressions of interest" from firms that may want to handle hauling the county's trash.

Greene said "It makes good sense to pursue rail-haul," and the only reason Gilchrist hadn't embraced the idea sooner was because of legal barriers to shipping garbage across state lines. The Supreme Court struck down any legal restrictions to inter-state trash in a 1978 ruling.

Simmons and the citizen opponents of the incinerator said they were not convinced by the apparent conversion of Gilchrist and the council members to the rail-haul idea in an election year.

Another aspect of the trash hauling controversy is the idea that the affluent county simply doesn't want to deal with its own garbage. "That keeps being brought up," said Peggy Erickson, leader of a citizens group opposing the incinerator. "But it's something that all densely populated areas may have to face," that is, hauling the garbage to more sparse rural areas.

Said Simmons: "It's not as if the county has any moral or political or economic responsibility for disposing of its own waste here. The question is can we dispose of it in a way that's acceptable to another jurisdiction.