I guess I should have been more specific. It's suddenly working again FOR ME (sorry if it isn't working for you) using Safari on both Mac and iPad.
I guess I'm surprised it isn't working on Firefox, my experience has been that Firefox is the browser you go to when any web page doesn't work...
The problem started a couple of weeks ago with many trains showing incomplete data and some completely missing from the map. Then, a few days ago, all trains disappeared from the map and have not returned. It’s not a browser issue.