Growth has been a fact of life in Herndon ever since the Washington & Old Dominion Railroad laid a rail line through the town in 1857, and coping with growth has been a never-ending, ever-changing battle for generations of town residents.

Today, Herndon is coping with a building boom that many say will rival the railroad's impact on the region. The parameters of the debate are being set by explosive commercial and office development within the town's 4.2 square-mile corporate limits.

Last year, the six-member Town Council approved 1.87 million square feet of office and commercial space, specially tailored for clean, high-tech industries. About 1.3 million square feet of that is under construction, led by the development of the Parkway Trade Center in a 100-acre industrial park in the town's southeastern corner, according to Peggy Dubynin, town director of planning.

The development of a high-tech industrial base is expected to touch off a surge in residential construction that should add 1,550 apartments, town houses and single-family homes to Herndon's stock of 4,730 housing units, according to planners. A major shopping center being developed by Giant Food Company is under construction at the corner of Elden Street and Herndon Parkway, Dubynin said.

The most dramatic indicator of Herndon's growth is its population, which has grown from 2,000 to 14,000 since 1960 and is expected to go to 18,000 in 15 years, Dubynin said.

Today, like the railroad more than a century ago, a major transporation project is playing a key role in the town's newest phase of development.

The opening of the $61 million Dulles Toll Road last year brought Herndon to within 25 minutes of Washington by car. The corridor, which skirts the southern edge of the city except for a short section that cuts through its industrial park, is slated for major development in Fairfax County.

Dulles International Airport, two miles away, also is serving as a magnet for high-tech industry. This year the state picked a 34-acre site southwest of Herndon for the development of a Center for Innovative Technology. The center will be in a 134-acre high-tech industrial park, which is expected to lure white-collar professionals to Herndon as well.

"The area's prestige has increased dramatically," said Barbara A. Byron, a Fairfax County planner. "The opening of the toll road has made the difference."

Herndon's comprehensive plan, first drafted 10 years ago, calls for a mix of residential, commercial and office development over the next decade and is designed to restore the bedroom community to its former status as a bustling commercial center, according to planners.

"Herndon will still be largely a commuter community, but hopefully more people will commute shorter distances and more people will live and work here," said planning director Dubynin. Currently, about 3,500 people do both, and planners say they hope to double that number by the end of the century, she said.

Through each cycle of growth, town officials have been forced to respond to changes, and in many cases they have devised imaginative ways to cope with the aches and pains of progress.

When the rail line closed in the late 1960s, for example, the town arranged to have the Northern Virginia Regional Park Authority take over the right-of-way and turn it into a hiking-biking path.

The old train depot, once slated for demolition to make way for a parking lot, was restored and coverted into a museum instead. It now serves as a focal point for community activities and has helped preserve Herndon's small-town flavor.

In the late 1970s, when rapid growth led to a problem with juvenile delinquency, the town responded with a massive parks and recreation construction program, said Edwin D. Martin, the town manager.

A community golf course opened in 1979, and a clubhouse was added a year later. The town's first community center was completed about the same time. A park for picnics and a sports field with tennis courts also were built.

After steady annual increases in crime, the police department last year began neighborhood watch and crime prevention programs that contributed to a 25 percent decrease in the reported crime rate in 1984, according to the police.

One of the town's most serious problems continues to be traffic congestion. More than 20,000 cars clog Herndon's major streets each day, creating the kind of rush-hour delays that require commuters to leave home earlier and spend more time on the road.

As a result, the accident rate in Herndon jumped 50 percent last year, forcing the department to assign additional officers to traffic control, said Lt. Robert C. Church, operations commander in the 26-officer department.

The town's long-planned solution, a circumferential parkway around Herndon's fringes to relieve traffic on residential and downtown streets, was first proposed in the 1950s. To date, four miles of parkway from Crestview Street to East Elden Street have been completed.

About half of the road has been built by developers at no cost to the city. The latest segment, about 8,300 feet of roadway, was dedicated last month, and construction of another segment is expected to get under way this year, according to planners.

Other roads are scheduled to be upgraded as well, depending on the availability of funds from the state. Even with the improvements, however, such strategies as timed signal lights will be needed to help traffic flow, planners said.

Vice Mayor Pamela S. Tennyson, who heads a six-member commission studying the future of Herndon's downtown, said the commission intends to study the feasibility of a minibus system for the town, one of several issues to be considered. The commission is planning to hire a consultant and hopes to issue a report this year with recommendations on revitalization that will take advantage of the area's booming growth.

"There's going to be a great many business people who need to eat lunch, so we have the potential for that kind of service," she said.

"We have the opportunity to do something unique, and I think we will. We certainly have the environment for it," said Tennyson.