Montgomery County taxi drivers, who had threatened to strike if they did not get relief from rising fuel costs, were granted an emergency rate increase yesterday of between 25 cents and $1 a ride by County Executive Charles W. Gilchrist.

The new rates, which cover all 260 of the county's taxicabs, go into effect at noon today.

Gilchrist's emergency action came as taxi service in the District was returning to near normal after a one-day strike Monday that left thousands of tourists, businessmen and other travelers stranded.

One faction of D.C. cab drivers, led by the Alliance of Taxicab Businessmen Inc., attempted to boycott Capitol Hill yesterday, but few cabbies appeared to participate. Cab drivers had been angered that their recent rate increase had been held to 10 cents a ride.

Norman Saunders, head of the D.c. alliance, said yesterday that if the D.C. Public Service Commissions does not act "substantively" in the next five days to reconsider the 10-cent-a-ride increase, cab drivers may stage a further job action, possibly a rush-hour boycott.

The new fare increases in Montgomery County will be billed as a surcharge on existing fares, based on the following sliding scale:

Rides now costing between 60 cents and $2.40 will carry a 25-cent surcharge.

Rides costing between $5 and $4.90, will carry a 50-cent surcharge.

Rides costing between $5 and $7.50 will carry a 75-cent surcharge.

Rides costing more than $7.50 will carry $1 surcharge.

Current Montgomery fares are 60 cents for the first 2/7ths of a mile and 10 cents for each additional 1/7th of a mile.

Gilchrist's action, which came after an emergency hearing Monday Night, was taken under authority granted him last year by the County Council. Last year's council action authorized the executive to adjust taxi rates after considering the recommendations of an advisory committee.

At the hearing, the drivers demaned an across-the-board fare increase of 50 cents per ride. Last Thursday, more than 80 Montgomery drivers staged a four-hour slowdown to underline their demands for relief.

"They certainly did bring it to our attention and certainly did get it expedited," said Gerald R. Cichy, director of the Department of Transportation.

Cichy said the drivers "basically . . . got what they asked (for), with an adjustment below and above to spread it more equitably among the users."

"We're pretty happy with it" (Gilchrist's decision)," said Bill Blumenauer, a driver and part-time dispatcher with Barwood Cab, the county's largest cab company. "It's a big help. It's enough to cover increased expenses. It's not enough to give us a cost-of-living raise."

One Barwood driver, Bobby Meadows, said yesterday "We are pleased that [Gilchrist] acted as swiftly as he did. We know the fight's not over yet. At least Round One has been resolved."

The increase in Montgomery fares, the first since March 1977, will last until the Taxi Service Advisory Committee recommends new rates, which will take between 60 and 120 days.

In other officials actions in Montgomery yesterday, the County Council formally aproved two items that had been decided on in earlier work sessions:

It lowered the property tax rate by about 35 cents per $1000 of assessed valuation. Under the new rates, the owner of a typical $80,000 house whose assessment rose about 10 percent over last year would get a tax bill about$17 lower than in 1979.

It also changed the formula for calculating the amoung of sewage flow from single family dwelling and town houses, and decided to use 80 percent of the regained capacity used for about 700 units of low-and moderate-income housing. The rest will be used for business enterprises and for private homes.