On every crossing? It might not be hard but it surely would be expensive. I'd guess that there are tens of thousands of these buttons around Greater Sydney, pos

On every crossing? It might not be hard but it surely would be expensive. I'd guess that there are tens of thousands of these buttons around Greater Sydney, possibly even in to the hundreds of. Also Sydney's crossing buttons are notably reliable. They last for decades and have been adopted across many other Australian cities and, IIRC, overseas somewhere.