Good Post in Chicago Group on Creating a Bus Tracker

There's a good thread going on in the Chicago group on creating a Bus Tracker for mobile phones with the use of data provided by the CTA.

I wanted to repost it to the Discussions Group to see if anyone wanted to abstract it a bit to think about applying it to other cities with transit data, or maybe even to other situations altogether.

By the final comment (as of now), I think they're really on to something good, that would be really useful to commuters:

> We create a TextMark (see www.textmarks.com) so that when
> people send a message to 41411 with the body
> "diycta STOP_ID_NUMBER" it forwards this requests on to
> our little script and returns the next three buses....

(full thread here: http://diycity.org/content/cta-bus-tracker-2d-barcodes )

Are there any other cities with the data that would allow this to work?

Is there any way of generalizing this idea and applying it to other frameworks?