A reply from our Bylaw Officer in Calgary who is associated with the city shelter:

We actually have working cats (not feral) in the lunch rooms at out Shepard landfill site. The staff there adopted a couple of cats that were abandoned at the landfill, started caring for them and tamed them. We spayed and neutered them, licensed them and give them their annual shots and check ups. The staff report that the rodent problems in the building have been solved and they think of their cats as part of the team. I found the article interesting, particularly the reasons why cats deter rodents. We are currently working with MEOW to look at the possibility of feral colonies and trap/neuter(spay) and release programs.
I have asked for more details. Yes, Calgary has yet to develop a TNSR program.