FLT CREW OF MD82 TOOK OFF FROM RWY 25 AT LAS WITHOUT CLRNC. DISTRS AND UNIQUE SWITCH POS ON THEIR ACFT ARE CONTRIBUTING FACTORS.

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WE WERE TAXIING FOR TKOF ON 25R IN LAS. WHEN WE WERE ABOUT A HALF MI FROM THE END OF THE RWY; THE FO ANSWERED A CALL FROM TWR AND WENT BACK TO CHKING THE NUMBERS FOR TKOF AND RUNNING THE CHKLIST AND DOING HIS PA TO THE FLT ATTENDANTS TO BE SEATED. AS I TAXIED ON TO THE RWY THE FO COPIED OUR FUEL AMOUNT AND TKOF TIME. HE THEN COMPLETED THE BEFORE TKOF CHK AND CALLED IT COMPLETE. I THEN CALLED; 'YOUR THROTTLES' AND I XFERRED CTL OF THE ACFT OVER TO HIM AS IT WAS HIS LEG. HE THEN SAID 'ARE WE POS AND HOLD?' I SAID 'NO; WE ARE CLRED FOR TKOF; LOOK AT THE LIGHT SWITCHES; THEY'RE ALL ON.' HE THEN SAID OK AND TOOK CTL OF THE ACFT (THE LNDG LIGHT SWITCHES; ON; IS OUR REMINDER THAT WE ARE CLRED FOR TKOF). THE FO COMPLETED A TEXTBOOK TKOF. THE RADIO WAS COMPLETELY SILENT EXCEPT FOR THAT ONE CALL THE TWR MADE TO US ON THE TXWY; QUITE A LONG TIME EARLIER. I OBSERVED NO OTHER ACFT ON THE RWYS 25R/25L SIDE OF THE ARPT. THE OTHER RWYS IN LAS VEGAS; RWYS 19L AND 19R; ARE NOT VISIBLE FROM THE E SIDE OF THE ARPT AND THEY ARE ON A DIFFERENT FREQ SO WE HAD NO IDEA WHAT WAS HAPPENING OVER THERE. AS WE CLBED THROUGH 1500 FT AGL; THE CTLR GAVE US A NUMBER TO CALL. AT THAT POINT I LOOKED AT THE LIGHT SWITCHES AND IT HIT ME. I WAS IN THE ONLY AIRPLANE IN OUR FLEET THAT HAS THE LIGHT SWITCHES INSTALLED BACKWARDS. MY HEART SUNK AND I KNEW WHAT HAD HAPPENED. WHEN I GOT ON THE GND I CALLED THE CTLR AND ASKED IF EVERYONE WAS OK. HE SAID YES AND THAT NO ONE HAD A PROB BUT THAT HE WOULD STILL HAVE TO RPT IT. I ASKED WHY HE DIDN'T SAY ANYTHING TO US WHEN HE SAW US MOVING BUT HE SAID HE WASN'T WATCHING OUR RWY. I REALIZE HE REALLY WASN'T SUPPOSED TO WATCH US. I AM JUST SO GLAD NO ONE WAS HURT. IT COULD HAVE BEEN A DISASTER. I THINK OUR LITTLE HELPFUL LIGHT SWITCH TECHNIQUE TO REMIND US OF OUR CLRNCS SHOULD HAVE BEEN DROPPED IMMEDIATELY WHEN OUR COMPANY ACQUIRED THAT OLD AIRPLANE WITH THE BACKWARD SWITCHES OR CHANGE THOSE SWITCHES TO MATCH ALL THE OTHER AIRPLANES. I ALSO DON'T LIKE THE TECHNIQUE OF THE TWR PUTTING ACFT INTO POS FOR 10 MINS AT A TIME WHILE THEY DEPART A HALF DOZEN AIRPLANES OFF OF A XING RWY THAT HAS A DIFFERENT FREQ. I KICK MYSELF FOR NOT USING MY CRM BETTER AND NOT ASKING FOR CLARIFICATION FROM THE TWR WHEN THE FO QUESTIONED WHETHER OR NOT WE WERE CLRED FOR TKOF. IT WAS JUST THAT I HAD THOSE LITTLE SWITCHES IN THE DOWN POS; THE WAY THEY ALWAYS HAVE BEEN FOR THOUSANDS OF TKOFS. RELYING ON TWO LITTLE SWITCHES INSTEAD OF A GOOD FO AND THE TWR TO CLARIFY OUR CLRNC WILL BE SOMETHING I WILL NEVER DO AGAIN.