Narrative:

Landed runway 23 late night in rain. Turned off active and was instructed to taxi to the apron via taxiway H to runway 15L onto that runway, then turn off at taxiway right. I thought we had cleared runway 23 prior to the runway 23/15R intersection. Combination of this, the late hour, the very dark terrain and the rain caused me to accidentally turn onto runway 15R when I saw the dimly lit red runway sign. Ground sounded somewhat amused as he informed us of our mistake and we immediately cleared at the very next taxiway, returned to taxiway hotel and continued our taxi to the gate without further incident. Note: only runway 24L and runway 23 were the active runways this evening, but I still cannot believe I turned onto the wrong runway. I saw the runway sign but did not recognize the 'right' when I should have been looking at an 'left.' I had studied the airport layout prior to the descent and approach and had mentally mapped out the taxi route I was expecting. Unfortunately, I did not count on ground instructing me to use a runway in the taxi sequence. I will know better next time. It would also help if we could get the signs a little brighter in this part of the airport.

Google
 

Original NASA ASRS Text

Title: AN S80 FLC TURNS ONTO THE WRONG RWY DURING A NIGHT TAXI OP IN THE RAIN AT CYYZ, ON.

Narrative: LANDED RWY 23 LATE NIGHT IN RAIN. TURNED OFF ACTIVE AND WAS INSTRUCTED TO TAXI TO THE APRON VIA TXWY H TO RWY 15L ONTO THAT RWY, THEN TURN OFF AT TXWY R. I THOUGHT WE HAD CLRED RWY 23 PRIOR TO THE RWY 23/15R INTXN. COMBINATION OF THIS, THE LATE HR, THE VERY DARK TERRAIN AND THE RAIN CAUSED ME TO ACCIDENTALLY TURN ONTO RWY 15R WHEN I SAW THE DIMLY LIT RED RWY SIGN. GND SOUNDED SOMEWHAT AMUSED AS HE INFORMED US OF OUR MISTAKE AND WE IMMEDIATELY CLRED AT THE VERY NEXT TXWY, RETURNED TO TXWY HOTEL AND CONTINUED OUR TAXI TO THE GATE WITHOUT FURTHER INCIDENT. NOTE: ONLY RWY 24L AND RWY 23 WERE THE ACTIVE RWYS THIS EVENING, BUT I STILL CANNOT BELIEVE I TURNED ONTO THE WRONG RWY. I SAW THE RWY SIGN BUT DID NOT RECOGNIZE THE 'R' WHEN I SHOULD HAVE BEEN LOOKING AT AN 'L.' I HAD STUDIED THE ARPT LAYOUT PRIOR TO THE DSCNT AND APCH AND HAD MENTALLY MAPPED OUT THE TAXI RTE I WAS EXPECTING. UNFORTUNATELY, I DID NOT COUNT ON GND INSTRUCTING ME TO USE A RWY IN THE TAXI SEQUENCE. I WILL KNOW BETTER NEXT TIME. IT WOULD ALSO HELP IF WE COULD GET THE SIGNS A LITTLE BRIGHTER IN THIS PART OF THE ARPT.

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.