I didn't hear what it was for, but the aircraft in question was the second UAL 757 flight (to IAD); I saw an EI 321 go around, then noticed that the UA 757 was still on the runway; it taxied back to the terminal under its own power, then - at about 2pm - it was towed away from T2, presumably towards the maintenance area.
Last edited by akerosid; 27th July 2012 at 23:07.
Reason: Additional info