B737-800. THE GATE MECHANIC RPTED THE #2 ENG WAS ON FIRE. THERE WAS NO FIRE WARNING IN THE COCKPIT.

Narrative

UPON ARR AT GATE AFTER ENG SHUTDOWN; A MECHANIC RAN INTO OUR COCKPIT TO INFORM US OUR #2 ENG WAS ON FIRE. HE REQUESTED WE FIRE THE FIRE BOTTLE. I ASKED HOW BAD THE FIRE WAS AS WE HAD NO WARNING IN THE COCKPIT. HE SAID IT WAS BAD SO MY FO RAN THE GND FIRE CHECKLIST AS I INFORM THE FA'S TO KEEP THE DEPLANING ORDERLY AND QUICK BECAUSE OF A FIRE. IT WAS ALSO AT THIS TIME I CALLED FIRE EMER EQUIPMENT TO ASSIST. THE MECHANIC LEFT AND RETURNED SAYING THE EXTINGUISHER KNOCKED DOWN THE FIRE; BUT IT WAS STILL GOING. WE FIRED THE 2ND BOTTLE JUST AS THE FIRE EQUIPMENT ARRIVED AND PUT OUT THE FIRE. THE FIRE CREW ADVISED US TO EVACUATE THE ACFT; WHICH WAS DONE BY THIS TIME. ALL PAX EXITED ON THEIR OWN INCLUDING OUR HANDICAPPED FOLKS ASSISTED BY THE FA'S. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE CREW WAS FLYING A B737-800 ACFT. THE CAPT RPTS THERE WAS A TAILPIPE FIRE IN THE #2 ENG. THE CAPT HAD SHUT DOWN THE ENG ABOUT TWO MINUTES BEFORE. CFR WAS REQUIRED TO PUT THE FIRE OUT. THE ACR REPLACED THE ENG. THE RPTR DOES NOT KNOW WHAT WENT WRONG WITH THE ENG.