After receiving hundreds of protests from transit users about the cost and complexity of its original bus-to-subway transfer plan, the Metro board has scheduled additional hearings this month on a revised proposal.

The new plan cuts the additional cost of such trips for many Prince George's County commuters who would transfer to trains at subway stations inside the District of Columbia. But it calls for a large increase in fares for Silver Spring commuters after rail service reaches that Montgomery County community next November.

Under the first plan proposed, it would have cost a District Heights resident in Prince George's $2.20 at the minimum for a combined bus-rail trip downtown, transferring at the Stadium-Armory station. The bus fare after March 21 will be $1.60. The lowest busrail fare is now proposed to be $1.95.

Silver Spring commuters face a jolt. The lowest proposed bus-rail combination fare downtown is proposed ot be $2.15 compared to the 11-bus fare after March 21 to $1.60.

If approved, the new fare structure would go into effect July 1, when Metro is scheduled to open its second rail line, extending 12 miles from the Stadium-Armory station through downtown Washington to Rossyln and National Airport in Arlington County.

The new fare structure also would apply to the Silver Spring rail line, which is expected to open next November, providing the first direct service into suburban Maryland. This is an extension of the line that now operates from downtown as far as the Rhode Island Avenue station in Northeast Washington.

Maryland riders would be served also by the Takoma station, just inside the District line.

Six public hearings are scheduled. Two of them will be held in Maryland, at 7:30 p.m. Mar. 14 at the Maryland-National Capital Park and Planning Commission, 8720 Georgia Ave., Silver Spring, and at 7:30 p.m. Mar. 22 at the Kenmore Junior High School, 200 Kenmoor Dr., Landover, Prince George's County. Maryland residents also may testify at District or Virginia hearings, listed at the end of this article.

Although the Metro hearings are strictly on the fare structure, the Montgomery County government has scheduled three separate forums of its own on plans for a county-operated feeder bus service in the Silver Spring-Takoma Park areas.

Details of these proposals are available from the county transportation department's information center at 468-4100. The forums will be held at 7:30 p.m. on Mar. 8 at Montgomery Blair High School, Silver Spring; Mar. 9 at Sligo Junior High School, Wheaton, and Mar. 10 at Takoma Park Junior High School.

All the proposed Metro fares are stated as round trips, rather than the traditional one way, because the transit authority plans to offer discounts only for people who travel in both directions.

Also, in this article, the fares cited are those to be charged during rush hours, when the largest surge of passengers - mostly commuters - uses public transit.

However figured, the new transit fare structure will be complicated. It involves a combination of bus fares, charged as a flat rate within the District and on a zone basis in the suburbs, and rail fares, charged everywhere on the basis of distance traveled.

After the bus-rail transfer plan goes into effect, the bus fares would be the same ones that are now slated to go into effect Mar. 21.

Maryland commuters who would transfer from buses to trains at stations inside the District would pay the same bus fare they now pay to get all the way downtown, plus a second fare on the train, but there would be a discount.

However, since the Silver Spring station is located within Maryland, commuters who transfer there would pay an intra-Maryland bus fare, which is as much as 50 cents cheaper than the bus fare to cross the District line into Washington. That lower bus fare becomes, in effect, a discount for transferring passengers.

Since a short trip by Metrobus within Maryland, under the present zone system, often costs as much as a long trip, many residents of Silver Spring taking only a short bus ride to a train station apparently face steep increases in total fares.

However, this situation may be eased by the introduction of the county's own proposed feeder bus service, which would charge fares lower than on the Metrobus system.

Officials have produced no clear explanation of the likely total costs to commuters.

The bus-rail transfer plan of the opening of the second rail line in July provides for rerouting numerous bus routes to serve or terminate at rail stations. For Maryland, this involves chiefly bus routes in the East Capitol Street, Pennsylvania Avenue and South Capitol Street corridors.

The District has settled a dispute with Prince George's County by agreeing to load and unload suburban buses on Pennsylvania Avenue near the Potamac Avenue near the potamac Avenue station (near the western end of Sousa Bridge across the Ancostia River), rather than diverting the buses to the Stadium-Armory station.

The forthcoming hearings will deal only with the Metrobus and Metrorail fare system, and not with the changes in the bus routes. The route changes are currently in the process of being approved by the Metro board following the earlier set of hearings last October and November.

A total of 157 witnesses presented testimony, much of it critical of the proposals, at those hearings. Since then 96 letters and several petitions bearing 747 names were submitted.

Following is a summary of the fare proposals which will be considered at this month's hearings: METRORAIL FARES

Rush Hours (6 to 9:30 a.m., 3 to 6:30 p.m. weekdays) - 50 cents to get aboard a train and ride for three "composite miles," with 10 cents for each additional composite mile. Composite miles are calculated by averaging the straight geographic distance and the actual travel distance between stations. If two stations are geographically six miles apart but a train must travel 10 miles between them over a roundabout route, the fare is charged for eight miles.

All Other Hours - 40 cents to get aboard and travel two composite miles, with 10 cents for each additional mile. The effect is to encourage short rides outside rush hour. From Dupont Circle to Judiciary Square, for example, the offpeak fare would be 40 cents, the same as on a bus. METROBUS FARES

The fares would be those that were approved last Thursday, to go into effect Mar. 21. During rush hours in Maryland, this would range from 80 cents to $1,40 to get all the way by bus from downtown Washington, or from 50 cents to $1.10 to get from various Maryland points to the Silver Spring Metrorail station. Free transfers would by provided byetween Metrobuses, but not between buses and trains. BUS-RAIL FARES

Occasional Trips - Full bus fare plus full train fare, paid separately. This would be substantially higher than present bus fares in many instances. For example, a one-way trip from Wheaton to downtown Washington that would cost 80 cents by bus in rush hour would cost $1.45 by bus and train. In off-peak hours, the trip would cost 70 cents by bus and $1.35 by bus and train, but would save considerable travel time.

Round Trip in One Day - This provides a discount of 40 cents or 50 cents for a round trip, depending upon the time of day.

A passenger boarding a bus pays the full fare, gets a special transfer and saves it. Arriving at the subway station, the passenger pays the full train fare downtown.

Returning, the passenger pays the full train fare and, arriving at the end of the train ride, validites the transfer that was obtained on the inbound trip. This is done with an automatic stamping device in the station concourse. The transfer will be accepted as a full bus fare to any destination in the District.

Several additional steps are needed for travel that involves more than one change of vehicle, such as bus-rail-bus.

This method was proposed last fall by Metro for all bus-rail commuters, but was criticized by many people as being too complicated. It "may appear to be complicated," Metro's planning office argued back in a recent report to the board, "but once the public has actually experienced the transfer procedure - they will find it no more difficult than the transfer procedure in effect today."

Commuter Pass - Metro plans to sell a two-week ticket. The card will have a peredetermined amount of rail fare value encoded onto magnetic tape on one side. The cost of each trip will be subtracted from this value by electronic devices installed in turnstile-like fare gates in each station concourse. On the other side, the card will be identified as a bus pass, good for unlimited free travel throughout the District and for a 50-cent basic bus fare in the suburbs, with additional zone fares to be paid in cash. The price of the ticket will be set at a level that, in effect, will give each rush-hour commuter a 75-cent daily discount from full fare for each round trip.

Here, according to Metro, are some sample round trip fares from Maryland points to downtown Washington:

From anywhere in the first Maryland zone, which includes Wheaton and Silver Spring station - All bus, $1.60; bus-rail combination, using transfer validation system, $2.40; proposed bus-rail pass, $2.15.

From College Park, in the second Maryland zone, transfering at the Rhode Island Avenue station - All bus, $2; bus-rail combination, transfer validation, $2.50; proposed bus-rail pass, $2.25.

From Seat Pleasant, in the first Maryland zone, transferring at the Stadium-Armory station - All bus, $1.60; bus-rail combination, transfer validation, $2.20; proposed bus-rail pass, $1.95.

From Bowie-Belair, in the fourth Maryland zone, transferring at the Stadium-Armory station - All bus, $2.80; bus-rail combination, transfer validation, $3.40; proposed bus-rail pass, $3.15. ELDERLY AND HANDICAPPED

Half fare (rounded downward to the closest nickel) for persons 65 or older and medically certified handicapped, at all hours. HEARINGS

All hearings will begin at 7:30 p.m. Witnesses may get on the list to testify at any hearing by telephoning 637-1092. Additional information is available by telephoning 637-1328. Metro lists the hearings as Docket B77-1.

March 14, Maryland-National Capital Park and Planning Commission, 8720 Georgia Ave., Silver Spring.

March 15, Lincoln Junior High School 16th and Irving Streets NW, Washington.

March 16, Swanson Junior School, 5800 N. Washington Blvd., Arlington.

March 21, Ballou High School, 4th and Trenton Streets SE, Washington.

March 22, Kenmoor Junior High School, 2500 Kenmoor Dr., Landover, Prince George's County.

March 23, Lee High School, 6540 Franconia Rd., Springfield, Fairfax County.