B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 189; Flight Crew Type 17000
Aircraft Equipment Problem Critical
Flight Crew Returned To Gate; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft
When taxiing for takeoff; a pilot in an aircraft in line for takeoff behind us broadcast that he was seeing flames coming from our number one engine. I continued to taxi onto the runway and subsequently exited the runway while we shut down the number one engine. We then proceeded through the QRH Engine Tailpipe Fire Checklist.On Tower frequency; I then asked for a better explanation of what had been seen. The pilot repeated that he saw flames but that they had extinguished. Two other aircraft in line also reported the same situation. While we coordinated with the Tower/Ground and Operations; we received a call a Flight Attendant that two passengers had seen flames from the number one engine (this report also was with flames now extinguished).Since all external reports indicated no fire indications and QRH guidance had been completed; we returned to the gate. Operations; Maintenance and Dispatch were notified. The aircraft was taken out of service.
[Report narrative contained no additional information.]
B737-700 flight crew reported returning to the gate after a pilot in an aircraft behind them reported a tailpipe fire.