On the issue of traps, many of you are confirming what is pretty well known, most rat traps are ineffective on the larger brown or Norway rats. They are too big for the trap to catch them. Rats are also super cautious around anything new.......traps, baits or poisons, so that makes it doubly hard to catch one using traps. And even when they do work, traps never catch them all, so while you may be able to thin the herd, mostly you only get the dumb ones. The smart ones survive to repopulate the colony.
And even with bait stations, they will not just walk in and start munching. It may take several days or even a week or so for them to get comfortable with something new. Best way to overcome that is to limit all access to other feed. Once they get hungry, caution goes out the window.