Wednesday 26 May 99- At 1529 hrs., FAA control tower notified the Massport Fire Dept. of a ground emergency on a Continental Airlines MD-80 reporting an engine fire. Stations 1 & 2 responded and found an interior fire on the left (#1) engine. E-1 crew pulled 200' of 1 3/4 preconnect line and extinguished the fire using only 50 gallons of agent. The aircraft had just pulled away from the gate when the pilot started its engines and the ground crew noticed that the left engine was on fire. Upon further investigation it was revealed that the fire was a tail pipe fire.