The neighbour who feeds the stray cats is attracting the rats.
Yep, when the cat-man's woman gave him the boot, there was a sharp decline a couple of weeks later. Only one rat in the past three weeks. Might be the stray cats needed to start working for a change, although I haven't see a lot of cats either...
You have to eliminate or restrict access to the rat's basic needs. Seems your rats have easy access to food and water, and you're probably stuck with dry safe shelter, like I was.
Get an electronic trap or live trap (kill them yourself), but you need unmarked dead rats. Place them with the neighbor's cat food. Either the neighbor will get the idea that he is feeding the rats, or the cats will get a taste for fresh rat meat. I couldn't reason with my neighbor about how bad it was to feed the stray cats, he also put out food daily for squirrels and birds. The stray cats only multiply, and need a fresh place to crap, and privacy to raise the baby strays, which creates problems for the whole neighborhood. I chucked my dead rats over the fence, into the back alley. Figured Cat-man would see them, or the owner's of the small businesses that share the alley, and they would also set some traps.
Anyway, it'll be an ongoing problem, it's an ideal environment for them, and they breed quick, something like every three months.
There was a water-pit trap, using a 5 gallon bucket I saw on the web. If I remember how I found the site, I'll post the link. Didn't try it, but thought about it (dog would probably eat the bait). Basically, you put a free spinning rod across the top, couple of inches down. The rod also passes through a corncob or small wooden platform. The rat will jump on the corncob/platform to feed on the bait, but will always wind up hanging upside down, as it will rotate. He can orient himself to climb or jump out, eventually drops into the bucket, about a 3rd full of water, and drowns. Bucket needs to be buried most the way to the top. Seemed like it would work, and repeatable, least until the bait runs out, or until the bucket has enough dead rats, that the rest can climb out off the dead the ones.
I searched and search, never found a homemade electric rat trap, other than wiring them up to the mains.
Here's my thread, which details much of what I found and tried, pictures included...
https://www.electro-tech-online.com/threads/rat-zapper.38448/#post304825