Narrative:

This [occurred during a very busy period]. A controller retired; and the facility is unable to adequately staff the tower. Due to this fact we are now on mandatory 6 day work weeks. I started my day and took over the schedule. I was left with two cics (including myself); and two certified professional controllers (cpcs); and they all needed to go on lunch break. I took position; started rotating people; and was working traffic. I worked for two hours and then took about a 15 minute break and came back to relieve the other controller in charge who was about to go over 2 hours. On this second session is when the incident happened:xa:01 tug #1 with an aircraft in tow called ground to reposition (would require crossing [the runway]). Ground pulled him up to the runway.xa:03 ground control coordinated with local control to cross runway after departing aircraft.xa:03 departing aircraft airborne. -Ground control crossed runway after aircraft departed.xa:05 local control cleared aircraft X for takeoff; overlooked runway crossing.xa:07 aircraft X radar contact.aircraft X was airborne before [taxiway intersection] at approximately 600 feet and was given an early left cross wind departure; tug #1 had almost finished crossing the runway; but was still partly on the active. Approximately 2;245 feet of separation was maintained; but the airport surface separation was lost.I was trying to balance the schedule; the traffic volume; the skeleton crew; and had an oversight. Recommendation would be a faster process to get staffing.

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Original NASA ASRS Text

Title: Local Controller allowed the Ground Controller to approve a tug towing an aircraft to cross the active runway. The Local Controller forgot about the tug crossing the runway and cleared an aircraft for takeoff. The tug towing the aircraft had not cleared the runway when the departing aircraft took off.

Narrative: This [occurred during a very busy period]. A controller retired; and the facility is unable to adequately staff the tower. Due to this fact we are now on mandatory 6 day work weeks. I started my day and took over the schedule. I was left with two CICs (including myself); and two Certified Professional Controllers (CPCs); and they all needed to go on lunch break. I took position; started rotating people; and was working traffic. I worked for two hours and then took about a 15 minute break and came back to relieve the other CIC who was about to go over 2 hours. On this second session is when the incident happened:XA:01 Tug #1 with an aircraft in tow called Ground to reposition (would require crossing [the Runway]). Ground pulled him up to the runway.XA:03 GC coordinated with LC to cross runway after departing aircraft.XA:03 Departing aircraft airborne. -GC crossed runway after aircraft departed.XA:05 LC cleared Aircraft X for takeoff; overlooked runway crossing.XA:07 Aircraft X radar contact.Aircraft X was airborne before [taxiway intersection] at approximately 600 feet and was given an early left cross wind departure; Tug #1 had almost finished crossing the runway; but was still partly on the active. Approximately 2;245 feet of separation was maintained; but the Airport Surface separation was lost.I was trying to balance the schedule; the traffic volume; the skeleton crew; and had an oversight. Recommendation would be a faster process to get staffing.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.