Of possible interest to some.
All railways, including those long dismantled, and at a serious level of detail when you zoom in.
You can choose map/sat background etc from the right hand menu, and other options like legend from the left hand menus.
Point and click on any line for more details, though it sometimes seems to take a few seconds to interrogate the database behind the scenes.
Obviously it's not absolutely spot on simply because track diagrams did change sometimes over the years, for example emergency sidings during the War, but as far as I can make out, the details on the dock lines, Walton Jnct and a few other places seem pretty accurate.
I'll get my anorak....