EARLY MORNING PART 135 CARGO FLT ACTIVITY RESULTS IN DAL RWY INCURSION.

Narrative

ON WEDNESDAY MORNING; I WAS TAXIING A C401 FOR A PART 135 SINGLE PLT CARGO FLT AT DAL. I WAS ON TWR FREQ. LEAVING AN FBO RAMP BY RWY 31R I WAS DIRECTED TO TAXI TO RWY 18; WHICH IS RARELY USED FOR NOISE REASONS. I WAS ALSO SOMEWHAT FATIGUED DUE TO THE HR OF DAY AND FLT SCHEDULE. THE USUAL TAXI PROCESS IS ACROSS RWY 18 TO RWY 13L. I REPEATED BACK TAXI TO RWY 18; BUT DUE TO FATIGUE AND HABIT; I TAXIED ON TXWY A ACROSS RWY 18 AND STOPPED IN THE RWY 13L RUN-UP AREA. REALIZING WHAT I HAD DONE BY ACCIDENT; I TOLD TWR (WHO WAS RUNNING GND ALSO) WHERE I WAS WHEN I STOPPED AND THEY JUST SAID HOLD SHORT RWY 13L. NO FURTHER MENTION FROM TWR WAS MADE. AFTER A RUN-UP; I DEPARTED RWY 13L WITHOUT FURTHER INCIDENT. THERE WERE NO ACFT ON FINAL TO EITHER RWY 18 OR RWY 13L DURING THIS ENTIRE PERIOD; NOR WERE THERE ANY CONFLICTING ACFT ON THE TXWYS IN THE VICINITY. THIS OCCURRENCE IS DUE TO PLT FATIGUE AND THE DARK; LATE HR. THIS COULD BE PREVENTED BY SUPPLYING PLTS DOING SINGLE PLT NIGHT 135 CARGO WITH ADDITIONAL SLEEP PERIODS.