Update: I do love this project I would really like this to be resolved so it’s perfect perhaps lights should stay on until the train reaches the next station?
As others have mentioned, there are more trains running than there are station LEDs, so in central London the LEDs would almost always be on, which didn't look as good.
For the MBTA in Boston we added LEDs in between each station, and even went further and added LEDs for each direction, but with only 4 lines it was much easier to put together - https://www.traintrackr.co.uk/product/mbta4
We're looking into this for London, but making it look good is significantly more complex with the number of lines and large interchange stations.
I think it would add another level of smoothness to it.
At peak times that would mean most lines would just be constantly lit
UPDATE: Maybe a LED per direction in tunnel would also be useful.
I seem to recall the actual control centres used to use a big map with the train lines drawn using a line of bulbs, and indicating trains buy a series of bulbs. Similar to this, http://photos.signalling.org/_datas/o/n/d/ondcx12zxd/i/uploa... .
There is no way a PCB this size could give an accurate representation. I'm not even sure that level of detail is even published by the TFL. But it shouldn't matter, this is clearly intended to be more ornamental than it is a functional tool for locating carriages.
So you'd leave(station=A,direction=0), then increment the tunnel A-B until you next had an arrive(station=B,0) when you'd decrement the tunnel section. Even branched tunnels Should Just Work ®. The tunnels are stacks, unless there are hidden sidings and such, things should add up. Bonus you change colour according to magnitude of $tunnelABC.
You'd need just under twice the LEDs though.
Ultimately the level of detail you're describing is not feasible with the aesthetic the designer was going for. This is one of those problems that appears much easier than it really is.
Plus, at risk of repeating myself, this is clearly intended to be more ornamental than it is a functional tool for locating carriages.
Absolutely. Appreciate your comments ... maybe when the kids leave home I'll get around to putting my money where my mouth is.
For the MBTA in Boston we did this, but their system is much less complex than London - https://www.traintrackr.co.uk/product/mbta4
Should be simple enough if you're up to it - prove you are worthy to display something like this :)
Experiment with blinking the leds synchronously (or not).
Circuit-board transit maps face the challenge of showing train flow with their few LEDs. Online transit maps have lots of pixels, but face the challenge of showing patterns of flow at time scales larger than a users glance.
One brainstormy idea that has come up in conversation, is to do something analogous to wind graphics like [1], which convey air motion using sample particles moving with unrealistic speed. Perhaps one might do something similar with trains?
[1] https://www.windy.com/-Pressure-pressure https://www.windfinder.com/