In the UK railways are mostly protected. Now, that may be a simple fence, which someone could climb over, but then they may find themselves reported, or caught

In the UK railways are mostly protected. Now, that may be a simple fence, which someone could climb over, but then they may find themselves reported, or caught on CCTV. It's a very obvious, very visible thing to do, and in urban areas railways are indeed protected pretty well. And remote triggering something like that is non-trivial. Roads are everywhere, most of them completely unprotected, and you don't actually have to physically and visibly interfere with the road.