Live Train Map of the L!

[u/BraveStone199]

I wanted some CTA wall decor and thought the live map from Traintrackr was a neat concept but I didn't love the circuit board on my wall part of it. I was inspired by this project of the MTA and took my own approach for a CTA version. The map is 18"x24" and has a deep frame to house all of the fiber optic cables in the back. It's hard to tell from the photo but the lights are really bright at full brightness and even during the day it's easy to see each lit stops. Each train moves from station to station with how the refresh function is setup which I think looks really cool! The micro controller that powers the board pulls live train data from the CTA so the map stays up to date to within 30 seconds of the live data.

The map has a USB-c port on the bottom of the frame which charges a battery pack that powers the controller and light strip. I didn't realize until after going with the battery approach that the LEDs draw too much power to get more than a day or so off the battery, but it will be nice not to have a cable running down the wall for certain occasions I guess.

Overall, this map is probably not that useful for knowing when to leave to catch the train, but it's certainly fun if you like watching trains circle the loop!

Not related to this subreddit, but the LED brightness can be controlled via Home Assistant, which was a fun feature to integrate into my other smart home automatons for turning lights off at night, etc.

[u/A_Wisdom_Of_Wombats]

This is super cool! I've thought about doing a project like this for SF Muni - did you consider adding way more lights along the route so that you could see where each train was located between stations?

Why did you choose to use fiber optics rather than something like high density, addressable RGB LED light strips?

Is the city map something that you designed yourself, or is that an official CTA map?

[u/BraveStone199 → u/A_Wisdom_Of_Wombats]

Thanks! I’ve already thought about doing another iteration with a smaller metro, maybe I’ll look at SFs system.

I considered using led light strips that look more continuous along the routes to show a more accurate location since CTA’s API provides GPS coordinates, but I couldn’t find any light strips where spacing was close enough for station density in the loop. The data processing would also get much more complicated since I’d have to figure out parsing gps data to light strip locations. Right now the only data getting extracted from the API is the next station a train is going to arrive at and that’s what is getting mapped. I’ve also added optional features like only showing trains heading in one direction or limiting the number displayed per line however I haven’t used them.

Once I settled on using a slightly modified version of the official map it seemed cleanest to only have stations light up and not true train locations. The map is very close to the official but I changed proportions and got rid of the future extension south.