CTA - Chicago Transit Authority
CTA Train Tracker API

CTA Train Tracker API 


The CTA Train Tracker SM API test provides a gateway into near-real-time CTA bus train estimated arrival times. You can use the official CTA Train Tracker service via Web or mobile device.

To use this API, you must agree to the Terms of Service and apply for an API key.

How train data gets into our system

Information in the CTA Train Tracker beta comes from data fed to CTA from its rail infrastructure (unlike buses, our current railcar fleet does not have GPS hardware). This data is then processed by software we use to monitor our rail system which also generates the predictions for train arrivals based on recent train travel times from one point to another. (The software is a product called QuicTrak, made by QEI, Inc.)

Prediction data are combined with other data and polished to help present information in the most meaningful way possible.

What the API does

The API makes it easy for developers to get specific, machine-readable information from CTA Train Tracker to incorporate estimated arrival/route progress information into innovative apps--mobile, online, or at locations.



A full set of documentation is available on a Web page and in PDF format, including details about API query string parameters and more.

Read Train Tracker Documentation Online (or  download PDF)


Apply for a key

You must first get a key to use our API. Use our API Key Application Form to request a key and we'll review your application as soon as possible. You should get a reply pretty quickly.


Things you should know

This service is in beta—it may not always be available and may be changed (see terms for complete details). Here are some notes about what you can expect from the data:

If you have any feedback, don't hesitate to write!

E-mail webmaster@transitchicago.com with your comments about our open data services, including this API.

More information

See Further Reading for more information about how you might use this feed, pointers and more! Also, be sure to check out our other information feeds, including the CTA Bus Tracker API, the Customer Alerts API and our Scheduled Service/GTFS data.

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