That one time that I heard it before that post, I heard two OCC operators distinctly, carrying on different conversations (and it wasn't a case of one's mic picking up another - the high-pitched chirp prior to them transmitting was present on both conversations). The one conversation I could distinguish was an operator talking to a unit about something west of Airdrie on highway 567, so I'd presume that was the A9 repeater. When that conversation ended, I heard the squawk that one hears (on the trunk freq) when OCC "drops the repeater". The other conversation could have been from A4, but I don't know for sure as not enough readable comms came through for me to tell what locale was being talked about.
For what it's worth, I did receive the Cochrane repeater (I generally listen to it thru A15) on another radio, and did not hear any comms thru OIL at the same time, so at least that one is not involved.
I haven't seen OIL myself so I can't answer what equipment comprises it. It's pretty much the #2 repeater (behind RYC) in Calgary though, complete with voice ID on the hour and I believe a phone patch too, so I would suspect it would have some semblance of "professional" gear on site.