I was watching some shunting at Peak Dale wood a few weeks back and I got talking to a man who knew of a website/app that told him the whereabouts of every locomotive on the rail network. However, I can't remember the name of it. So he could tell what 66s were hidden in the sidings at Great Rocks from merely looking at his phone or laptop.
Does anyone know of an app/website that tells you what duties each locomotive is on on a particular day?