The federal Department of Housing and Urban Development has tentatively approved a $3.7 million subsidy for an 84-unit housing complex for the elderly in downtown Capitol Heights.

City officials said they received word of the approval by telephone last week.

Construction of the complex, called Gateway Village, should begin in a year at the three-acre site just south of the 6000 block of Central Avenue near Suffolk Avenue, said Assistant City Manager Ralph Lange.

"This is a major accomplishment for the town; a real shot in the arm for us," the assistant city manager said. "We're also spurring new business in the community because the people who own the land want to use the money to purchase new fire department equipment for the city."

This week, the Town Council approved a law enforcement Explorer's program for the city's police department.

Explorer programs, under which teen-agers learn about law enforcement procedures but do not participate in arresting suspects, have been established by police in both Montgomery and Fairfax counties.

In Montgomery, police have assigned Explorers under the legal drinking age to purchase liquor from stores and bars; some of the owners have been subsequently charged.

Lange said the Explorers would function as "sort of a farm club for the police department."