The real RC-AC's would be used in airports, vetrinary clinics, and humane societies. They would work like trains, except follow lines that are on the ground. They will follow the lines on the ground, and if someone or something gets in the way, it stops and waits until the object moves, (The ultrasonic sensors act like cameras). When one of these comes near a junction of lines, a operator woud control all the crates just like trains, by telling them to go left, or right, by using switches, buttons, or levers. these also would come in different sizes depending on the size of the animal.
You know how the airports get the animals into the cargo hold of a plane? Well if not, I will tell you. First, the workers put the crates on the conveyor belt, Second, the crates are transported onto a luggage truck, Third, the truck drives toward the plane, and finally, they are put on another conveyor that leads to the cargo hold. These crates reduce the work done by the employees, and release no CO2 in the air, because there is no need for a luggage truck. All the workers have to do is put the animal in the crate, and the crate moves toward the cargo hold by following line routes. The operator would just steer the crate into the cargo hold. Simple, right?
Since I decided not too post an LDD, Here are some more pictures.