The brown rat (Rattus norvegicus), also called the Norway rat, lives at ground level: cellars, crawl spaces, courtyards, sewer networks. It swims well, digs readily under slabs and uses the same runs along the walls day after day, leaving marks that a trained eye reads easily.
At home or in your shop, the job therefore starts with those runs: where does it travel, where does it come from, what is it eating? Tamper-resistant bait stations go where it actually moves, any route up through the drains is identified, and the holes and cracks it uses to get in are then sealed.