I work in rail. In any automated system, you don't assume anything; you either know it absolutely (fail-safe systems), or you revert to pure manual control at l

I work in rail. In any automated system, you don't assume anything; you either know it absolutely (fail-safe systems), or you revert to pure manual control at line-of-sight of the operator, which is far slower. And yes, all the technology has been tested together. Before a train can enter a new region of authority, it must have permission from that authority, which means they must prove that the train can work with the local tech.