A 29-year-old Damascus man was killed and six other people were injured in an early morning, head-on collision on Rte. 355 in Gaithersburg, Montgomery County police reported yesterday.

Harry V. Stipe, of 26813 Grace Ct., Damascus, was driving south on Rte. 355 with three passengers in his car when another car smashed head on into his on the bridge over the B & O Railroad tracks near East Diamond Avenue at 1:45 a.m., police said.

According to police, the driver of the northbound car, 40-year-old Clayton E. Lawrence of Gaithersburg, who works for the county Department of Transportation, was driving on the wrong side of the road.

Stipe was taken to Shady Grove Adventist Hospital in Rockville where he died of multiple injuries. Dr. John Ball, county medical examiner, has ordered an autopsy.

Two passengers in Stipe's car, Holly Keebler, 21, of 408 First St., Rockville, and Linda Mertz, 24, of 944 Merust La., Gaithersburg, were listed in stable condition at Montgomery General Hospital. A third passenger, Willie T. Hardy, 31, of 1971 Crystal Rock Rd., also was listed in stable condition at Shady Grove Adventist Hospital.

Police identified the passengers in Lawrence's car as Leon Shipe, 40, of 18447 Lost Knife Circle, Gaithersburg, and June Aldridge, 45, of the same address. They were listed in stable condition at Adventist and Montgomery hospitals, respectively.

Charges against Lawrence, who is in critical condition at Suburban Hospital in Bethesda, are pending during the investigation of an incident that happened 15 minutes before the collision, at the Walnut Hill Shopping Center. There, a car was rammed and pushed 100 feet by a car matching the description of Lawrance's car, police said.