LOSS OF SEPARATION BTWN BA32 ON TKOF ROLL AND A SECOND BA32 XING THE SAME RWY. TKOF ABORTED.

Narrative

I BELIEVE THE CAUSE OF THIS INCIDENT WAS FIRST: THE TWR SAID A CTLR TRAINEE WAS WORKING GND CTL AND DIDN'T REALIZE THAT THE RWY WAS ACTIVE. BASED ON THAT I FEEL THE SUPVR SHOULD HAVE BEEN PAYING MORE ATTN TO THE SIT AND/OR THE TRAINEE NEEDED MORE TRAINING PRIOR TO WORKING ACTUAL FLTS. SECOND: THE MECHS REPOSITIONING THE ACFT COULD HAVE EASILY AVOIDED THE INCURSION HAD THEY JUST LOOKED L AND R BEFORE XING A RWY. MORE EXTENSIVE TRAINING MAY BE NEEDED FOR MECHS ON ARPT TAXI OPS/SIGNS/CLRNCS; ETC. TWR ISSUED A TKOF CLRNC FROM RWY 31 WITH A R TURN TO 360 DEGS AFTER DEP. IT WAS THE FO'S LEG. JUST PRIOR TO THE FO SETTING TKOF PWR I SAW A JETSTREAM 32 APPEAR FROM BEHIND THE B757 TO THE R OF THE RWY. I NOTICED THE SPD MAY BE INSUFFICIENT TO STOP PRIOR TO THE RWY SO I KEPT WATCHING UNTIL I DETERMINED THAT THE ACFT WOULD NOT STOP AT WHICH POINT I CALLED 'ABORT MY ACFT' AND ABORTED THE TKOF PRIOR TO THE '70 KTS' CALL. THE OTHER ACFT CONTINUED ONTO RWY 31 AND MADE A R TURN DOWN THE RWY; THEN A L TURN ONTO TXWY B AND HELD SHORT OF RWY 30R. TWR WAS TOLD WE ABORTED DUE TO AN ACFT ON THE RWY. TWR ISSUED INSTRUCTIONS TO BACK TAXI ON RWY 31 INTO POS AND HOLD AGAIN. WE SAT IN POS UNTIL THE JETSTREAM WAS CLRED TO CROSS RWY 30R AT BRAVO INTXN. ONCE THE JETSTREAM WAS CLR TWR REISSUED US A TKOF CLRNC ON RWY 31 AND THE FLT CONTINUED TO BRL WITHOUT FURTHER INCIDENT.