ACR X RWY INCURSION HAD LTSS WITH ACR Y ON TKOF ROLL.

Narrative

ACR X FROM SPOT '6' WAS CLRED TO TAXI TO RWY 9L VIA K3; K. WE TAXIED ONTO K3; BUT WENT PAST K ACROSS RWY 9R (AN ACTIVE RWY) ONTO TXWY M. I; THE FO; WAS GETTING THE WT AND BAL AND MISSED HELPING THE CAPT WITH THE TURN. ACR Y WAS TAKING OFF ABORTED TKOF AND CLRED THE RWY. K3 IS AN EXIT FROM AN ALLEYWAY THAT ALSO CROSSES AN ACTIVE RWY AND SHOULD BE MARKED WITH FLASHING LIGHTS TO PREVENT THIS FROM HAPPENING AGAIN. ALSO NO CHKLISTS WHILE TURNING. SUPPLEMENTAL INFO FROM ACN 302610: ACR Y CLRED INTO POS AND HOLD ON RWY 9L PHL. WHEN CLRED FOR TKOF I TURNED ACFT OVER TO FO. HE ADDED PWR I TURNED ON AL EXTERNAL LIGHTS; AND CALLED 80 KTS; AT THAT TIME FO SAW ACR X TAXIING TOWARD AND ONTO OUR RWY. I LOOKED UP SAW X AND REJECTED TKOF. WE STOPPED APPROX 2000 FT FROM X. WE TAXIED OFF RWY AND TWR CLRED US TO TAXI BACK FOR TKOF. SUPPLEMENTAL INFO FROM ACN 302781: ACFT Y ON TKOF ROLL ACFT X FAILED TO FOLLOW PROPER TAXI INSTRUCTIONS AND CROSSED RWY IN FRONT OF DEPARTING ACFT Y. ACFT Y ABORTED TKOF AND TURNED OFF AT TXWY 950 FT FROM TXWY ACFT X CROSSED AT. PLT OF ACFT X STATED ON PHONE CONVERSATION THAT HE 'THOUGHT' BECAUSE OF THE TFC ON THE TXWY HE WAS ASSIGNED AWAITING DEP WE WANTED HIM ON THE OTHER SIDE OF THE RWY. TAXI RTE ISSUED WAS VIA KILO 3 AND KILO TO RWY 9L. ACFT WENT ACROSS AT KILO 3 TO TXWY MIKE.