I made this as a test of what can be done locally in the browser without a backend, and because I was frustrated with certain things missing from traditional maps.

You can draw routes around the tube network, get time heatmaps from any station, use alternate maps, disable lines, etc.

It should work in latest Firefox and Chrome desktop, Chrome mobile, and hopefully Safari (though I couldn't test it myself yet). IE definitely doesn't work until I've had more time to play with it, it doesn't support maps/sets without polyfill...

I'd really appreciate screenshots from Safari if anyone feels particularly helpful :P