There is no one, simple, foolproof system for combatting serious theft. Multiple systems are needed. Apps and GPS systems don't talk to each other. Systems reliant on mobile (cell) phone systems can be defeated by moving outside tower coverage areas - of which there are still many, today. GPS tracking systems can be blocked by concrete walls and heavy roofing materials.
Simple substantial security is the best 1st step. Lock up expensive items in secure, well-lit buildings or secure rooms.
Position infra-red trail cameras along routes into or out of the area, that can clearly record number plates or faces.
Thieves have to move in or out of the selected target area, you catch them out while they are travelling to and from their target area, when they are relaxed, after they have their facial disguise removed or before they put it on.
You can see how many thieves/rapists/crims are caught by security cameras positioned at railway stations/busports/shops, usually a considerable distance from the crime scene.
They think they're safe, they are either still in the planning stages or they've completed the crime, and they think they've got away with it.
6 engines would need a commercial vehicle to carry them away, you wouldn't be throwing them in the back of a family sedan or estate wagon.
It would have been a big enclosed van, thus narrowing the vehicle search.
Traffic cameras record the movement of every vehicle through intersections with amazing clarity, and it's important that thefts are discovered and reported quickly, while the trail is still hot, and CCTV records are still available.