Dealing with railroad property can be tricky. There are basically 3 ways railroad acquired rights to property: 1. they buy a strip (usually 100' wide) outright, called fee simple title; 2. they obtain an easement; 3. they file condemnation proceedings and take the property.
Every State has their own set of laws regarding such things. In Illinois, there may be language in a deed that the property "is to revert back to the owners", but those reverters are only good for 40 years. If the RR got only an easement, the ownership is more tricky...at any rate, your deed probably excepted the RR, so you wouldn't legally have a claim. If the property was taken in condemnation, then there are provisions for reverting back to original owners. Many conveyances are ambiguos and hard to interpret by the layman. An attorney or title company is your best approach for your real estate questions.
RR are notorious for being difficult to deal with. Be patient with their legal department relative to getting a sewer easement.
I stongly urge you to refrain from "booby traps" and stick with the camera scheme, and get law enforcement involved.
