The Montgomery County government will tell Metro officials at a hearing this week that Metro's proposed bus-rail transfer plan is too complicated, economically faulty, unduly expensive for riders, costly to administer and subject to widespread abuse.

Instead of marketing a novel bus-rail pass starting July 1, when Metro's second 12-mile subway line is scheduled to go into service, Metro should adopt a simple transfer that lets a passenger get off a train and onto a bus without playing a second fare, according to the country.

The county also will recommend what it calls a "tapered" fare, with a lower cost for each mile traveled on longer trips than on shorter ones. Under the now-proposed fare, the staff predicted, trains - especially on such long lines as the one being built to Rockville and Shady Grove - will run empty because passengers will resist the high cost.

The staff memoranda that led to the decision by County Executive James P. Gleason and the County Council contained perhaps the most scathing public criticism of Metro made by a local government participating in the transit program.

Cleatus E. Barnett, Montgoemery's director on the Metro board, who supported the original plan, said the criticisms persuaded him to support the county's new proposals new proposals.

"While on the surface (Metro's) proposals may seem reasonable," County Transportation Director Richard J. Lynch declared in one memo, "the actual application . . . produces instances of inequity and may be self-defeating by virtue of their complexity."

Lynch noted that transit passengers in the Wheaton-Silver Spring area, who after May 21 will pay $1.60 for a round trip bus ride to downtown Washington, would pay $2.25 for a combined bus-subway trip. A one-way bus trip that costs 80 cents would cost $150 by bus and subway, with only a three-minute time saving for a rider from Wheaton.

The bus-rail transfer plan is not the only likely controversy to emerge at this week's hearings. In the District of Columbia, the hearings will consider an increase of the rush-hour city bus fare from 40 cents to 50 cents, the first rise since 1970.

This week's hearings, all starting at 7:30 p.m., will be held Monday at the Maryland-National Capital Park and Planning Commission, 8787 Georgia Ave., Silver Spring; Tuesday at Lincoln Junior High School, 16th and Irving Streets and NW, and Wednesday at Swanson Junior High School, 5800 N.Washington St., Arlington. More hearings will be held next week.

Metro's officially proposed rail-bus transfer plan is a revised version of one proposed earlier by Metro planners, and attacked at public hearings last fall as too complicated and too costly for many riders.

Hearings on the earlier plan focused on riders from Southeast Washinton, Prince George's County and Northern Virginia - the areas to be served by the second subway line that opens on July 1.

Because of strong criticism from residents of those areas, the proposals were adjusted to produce generally lower fares for them.

However, whatever fare is adopted for routes serving those are as salso would apply to a line scheduled to open late this year, probably Nov. 1, from the Rhode Island Avenue station on the existing five-mile line to the Silver Spring station.

Edward Daniel, Montgomery County transportation planning director, and Colin Alter of the Montgomery County Planning board, both analyzed the impact on riders from their county, and told their bosses that the effect would be ruinous.

When Metro's proposal was outlined to the County Council on Thursday evening, its president, John Menke, commented: "I don't know where the computer is that can figure out the Metrorail-Metrobus fare structure."

For commuters, Metro proposes to sell a $10 ticket that would be used as a pass on the buses and as a ticket worth $7.50 on the trains. Train fares would have to be supplemented when the $7.50 runs out.

Lynch, in his memo, said the pass would be economical only for someone using it without fail for five round trips each week.

Morever, he wrote, it would be "open to wide abuse between bus-only and rail-only passengers," since bus passengers could buy an use a pass for $10 or more worth of trips for two weeks, and then sell it at a discount, to persons wanting to take $7.50 worth of train trips.

Lynch said the pass would be costly to administer.

As an economist, County Council member Neal Potter said he found it "astonishing" that Metro did not seem to realize that fares lower than those it proposes would attract more passengers in offpeak hours.

Metro's plan has reduced fares for offpeak riders only for very short trips - "the Washington lunch trade," Lynch said.

Instead of the bus-rail pass plan, and another plan - even more complicated - for a one-day round trip by bus and rail, Montgomery County will support a plan for Metro to issue a transfer from trains to buses, but not the other way around. A transfer would be sold from a vending machine in a train station for 5 cents.

This means, generally, that a rider would pay a full bus fare and a full train fare to get downtown in the morning, but would pay only a train fare plus 5 cents to get home in the evening.

Instead of charging a peak-hour train fare of 50 cents for the first three miles traveled, and 10 cents per mile thereafter, with no maximum, Montgomery County proposed these fares:

25 cents for the first two miles, then 10 cents for each of the next eight miles, then 5 cents a mile beyond, with lower fares in offpeak hours.

Montgomery County officials estimated that increased ridership would offset much if not all of the revenue loss from the lower fare per mile.