There could be a lot of rats and trapping them will never rid you of them. I would make a trip to your local farm store and purchase some rodent bombs (look like a big fire cracker) light one up put it down the hole as far as you can and use a leaf blower to force smoke down the tunnels. Done in one time.

Used to go to the local dump as a kid with my ,22 and have a blast.

trapping rats is fun but if you have obvious rat problems you have a lot of rats, as fast as they breed it may take awhile and you probably won't get them all.
For outside the home rats it's hard to beat rat blocks, change to a different formula after a week or so. It will knock them down fast. Never used the bombs, not sure how that would work with an extensive tunnels, but YMMV

or plug the hole with a rag

Been there done that as a kid.