MyChicago Train Tracker app shows realtime train times for CTA riders
If you know the stop number, you can write and call directly.
If you do not know the stop number, you can reach the names of the stops and make a selection by choosing your route.
You can save as many stops as you want.
The application uses CTA data to show realtime train times, when the trains will arrive at the stop
It is not official Cta Train Tracker app, but this app makes use of CTA API