Date: 201605
Local time of day: 0601-1200
Location: DEN.Airport, CO
Flight conditions: VMC
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground DEN
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Confusion
Second reporter function: Pilot Flying; First Officer
Anomaly: Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Detector: Person Air Traffic Control; Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented
Contributing factors: Airport; Human Factors
Primary problem: Human Factors

Narrative: After leaving ramp exit; DEN ground clearance is to taxi Mike to RWY 17L hold short of taxiway ED. This is a runway change from ramp controls expect RWY 17R for our SID. Holding short of ED there was no other ground traffic in the immediate area. First officer was heads down working on the new take off data for RWY 17L. Ground control clearance was to taxi on ED and hold short of RWY 17R approach. First officer acknowledged and went back heads down. I was thinking in my mind this was an unusual clearance because I was geared for RWY 17L. The RWY 17R part did not register as we were not crossing any active runways. At my 10 to 11 o'clock view I noticed another B737 on approach to RWY 17R at about 300 to 400 AGL. It appeared it was going around. I stopped the aircraft just as ground control asked if we were holding short of RWY 17R approach. If you extend the west edge of RWY 17R to the north; the nose of our aircraft was about one aircraft length to the west of that imaginary line. We told ground control that we both understood hold short of RWY 17L which is what we normally expect. After we continued to taxi to RWY 17L we noticed the hold short markings east of RWY 17R for the approach for aircraft taxiing west on ED. As many times as I have taken the same taxi route east on ED; I have never noticed the hold short markings. After departure; DEN departure advised us to call DEN tower when landed. I advised we would call in 2+ hours. When in ZZZ I called and they were too busy to take my statement and there was a shift change since we took off and the person answering had no knowledge of the incident. I called again in 5 hours after the next flight and same person said to call back in [four days].


Second narrative: We pushed off the gate got clearance from ground to taxi M hold short of ED and to expect 17L. I was heads down putting in final numbers when ground told us to turn right on ED and hold short of 17R approach. The captain made the turn and I was still heads down and we inadvertently crossed over the 17R hold point. We noticed this just as we crossed thinking the hold short point was further down not immediately following the turn on to ED. The captain stopped immediately and ground called asking if we were holding short of 17R approach.


Synopsis: B737 flight crew reported inadvertently crossing the hold bars on Taxiway ED for the Runway 17R extension at DEN causing an aircraft on final to go-around.