Narrative:

We were operating aircraft X mdw to atl. We backed out of gate X and got our taxi instructions to runway 31C. Taxi on txwys P, G to runway 31C cleared to cross runway 31R. On the other side of runway 31C on taxiway P, ground told us to switch to tower because they were going to get us right out. There were 2 B737's sitting side by side short of runway 31C. I was starting the #1 engine at the time in the event we were next. The captain I believe because he saw we could not get around the 1ST B737 on taxiway G, made a left at taxiway K so we could get around the B737. As far as I can remember there were no runway markings for runway 31R and the ones I could see were very light. As we rounded the corner and pulled up next to the B737, the tower asked us to let them know if we were going to do that again because we were told we encroached onto the end of runway 31R. I would include a copy of our approach plate, but I don't have a copy machine. But looking at plate 10-9 of mdw the area we were in was all taxiway, so the captain and I were both confused on how we could have ever encroached on runway 31R. As I said before I did not see any markings and the ones we could see were very worn.

Google
 

Original NASA ASRS Text

Title: B737 FLC BLUNDERS ONTO ACTIVE RWY AT MDW.

Narrative: WE WERE OPERATING ACFT X MDW TO ATL. WE BACKED OUT OF GATE X AND GOT OUR TAXI INSTRUCTIONS TO RWY 31C. TAXI ON TXWYS P, G TO RWY 31C CLRED TO CROSS RWY 31R. ON THE OTHER SIDE OF RWY 31C ON TXWY P, GND TOLD US TO SWITCH TO TWR BECAUSE THEY WERE GOING TO GET US RIGHT OUT. THERE WERE 2 B737'S SITTING SIDE BY SIDE SHORT OF RWY 31C. I WAS STARTING THE #1 ENG AT THE TIME IN THE EVENT WE WERE NEXT. THE CAPT I BELIEVE BECAUSE HE SAW WE COULD NOT GET AROUND THE 1ST B737 ON TXWY G, MADE A L AT TXWY K SO WE COULD GET AROUND THE B737. AS FAR AS I CAN REMEMBER THERE WERE NO RWY MARKINGS FOR RWY 31R AND THE ONES I COULD SEE WERE VERY LIGHT. AS WE ROUNDED THE CORNER AND PULLED UP NEXT TO THE B737, THE TWR ASKED US TO LET THEM KNOW IF WE WERE GOING TO DO THAT AGAIN BECAUSE WE WERE TOLD WE ENCROACHED ONTO THE END OF RWY 31R. I WOULD INCLUDE A COPY OF OUR APCH PLATE, BUT I DON'T HAVE A COPY MACHINE. BUT LOOKING AT PLATE 10-9 OF MDW THE AREA WE WERE IN WAS ALL TXWY, SO THE CAPT AND I WERE BOTH CONFUSED ON HOW WE COULD HAVE EVER ENCROACHED ON RWY 31R. AS I SAID BEFORE I DID NOT SEE ANY MARKINGS AND THE ONES WE COULD SEE WERE VERY WORN.

Data retrieved from NASA's ASRS site as of July 2007 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.