Todd, there seems to be little, if any, information about damage to the OR&L on 12-07-41. It did put the railroad on a wartime footing almost immediately, with headlights blacked out, etc.
As Jerry mentioned in his post, there was three foot gauge track all over the Pearl Harbor complex, so some damage during the attack undoubtedly occurred. Much of the trackage on the docks was still there, although not in use of course, when I was stationed at Subase Pearl in the early 1960's. I've never been able to see any railroad activity other than rails in place on docks in any pictures I've seen taken during the attack.
Ed