CTA Train Tracker Estimated Arrivals: Notes & Help
Train Tracker sm provides estimated arrival times for 'L' train service across Chicago. It's available in your browser and on Web-enabled mobile devices.
See also: CTA Train Tracker Map Help
On this page:
Help us make CTA Train Tracker better by filling out this quick CTA Train Tracker survey.
Here's what's available in this release of CTA Train Tracker:
- Estimated train arrival times for stations based on "live" train information, using location data we have for trains that are in service.
- Estimated arrival times per train, by clicking on a train in a list of station results.
- Up to two scheduled arrival times are shown when there are only one or no predictions for a given boarding position at your station.
- An easy-to-use interface designed for quick access to the information you want, whether you're using the desktop or mobile version.
- Integrated Customer Alerts shown in the event planned work or an unavoidable delay affects service (and/or the reliability of predictions).
- The ability to customize how information is presented to you. Options include setting how many arrivals are shown, or grouping arrivals by route or track.
- Text messaging capabilities that allow you to get information from CTA Train Tracker by text.
- Stops you recently viewed are remembered, and you can flag stops as "favorites" for easy access later.
- The ability to search for stops by name.
- The ability to search for stops near you, where location data is available.
In later phases, we'll be adding a number of additional features. Check back here periodically to see what's new!
Stops Near Me
This feature helps you more quickly jump to the info you need, based on your location. Modern phones and web browsers can find your location quickly and with pretty good accuracy by using either GPS hardware or using WiFi hardware to detect nearby hotspots.
If you use this feature, your computer or device will tell us where you are (in latitude and longitude), along with a margin of error and some other info. We then check against our database of train stations to tell you which ones are closest.
If the margin of error is too great, we won't be able to make suggestions, but you can always pick a route and station by name or search for stations, by name.
While this service works really well when you have the right hardware, there are a number of circumstances, due to limitations modern phones have as well as physical barriers (like subways, which are underground and away from the signals that are needed to detect location).
Here are the common types of errors you might receive and why:
- The info we received wasn't accurate enough.
If you're underground, in a sturdy building or don't have WiFi or GPS enabled, your browser or device might give us a location, but it might not be precise enough for us to make any suggestions that are likely to be helpful.
- We don't have permission to see your location.
Your browser or device has told us we don't have permission. If you'd like us to make a suggestion based on location, if your device asks you whether you'd like us to see your location, you'll need to allow it for this to work.
Also, some capable devices may be set to reject all location information requests from websites, such as some Blackberry devices--you may need to set your browser options to enable this feature. Also, if you've rejected a request from us in the past, you may need to reset browser permissions in order for you to be prompted again.
- Information wasn't available to us.
Your computer or device told us that location information wasn't available. It might not be possible for your location to be detected if you're in certain places, like underground, or don't have a reliable connection to the Internet.
- The operation timed out.
If it takes a long time for your location information to be provided to us, the operation can time out. It might work if you try again.
- A network or server problem occurred.
If your computer or device doesn't have a reliable network connection, or for some reason our servers couldn't fulfill your request, you won't be able to see suggestions.
Follow This Train
When you are looking at a list of estimated arrivals for a station, you can pick the train you plan to board from the list and watch its progress as it approaches you. Then, you can keep watching and see when you'll arrive at the stop you're going to.
When following a train with this feature, you can also then click stations further down-route and see arrivals for that station (which can be especially handy if you're taking a train to a station specifically to transfer to another train).
This data is only available for trains that are in-service (not trains that have yet to depart).
How does it work?
This system looks at where in-service trains are and makes estimations based on recent travel times from one place to another, and also shows scheduled information when predictions aren't available due to a train not being close enough yet to do so.
Why does it sometimes show scheduled arrival/departure times?
"Live" predictions are only available for trains once they've left their terminal. Up until a train leaves its terminal, we show scheduled arrivals instead. At terminals themselves, only scheduled departures are shown. Note that scheduled departures may vary slightly in the event that service is being modified by route managers to maintain even service levels.
In some cases, scheduled arrivals don't provide a specific destination, but a general direction. Once a train leaves and is in service, however, more information, such as specific run number and destination will be shown on its "live" predictions.
The latest version of the Train Tracker now shows up to two scheduled arrivals, while service is running, for every place a train stops.
If this is just in testing, how reliable is it?
We've been testing and refining predictions now since several months before the service was initially launched at the start of 2011. This service is still in testing, though, so we do expect that there will be an occasional hiccup.
If you spot something you think was in error, we want you to let us know. Also, to make sure we're giving only good information, we may not provide predictions in the event that trains are rerouted in such a way that predictions won't be reliable.
What does it mean when the results show "---" instead of a train prediction?
An entry that shows "---" indicates a train is expected to be on the way soon, but that we need more information to give you a reliable estimate. It's basically a way to handle the unexpected without giving you information we can't be sure is reasonably reliable.
What does it mean when it says "Delayed"?
This indicates that a train has been in the same place for a few minutes for any reason. Once the train starts moving, predictions will start being shown again.
The Web site is alerting me that predictions may be affected by something. Why?
Because this service is still in testing and development, there are certain circumstances where major track work or unplanned reroutes/delays can negatively affect the quality of predictions. Because we are careful to avoid giving information that's not likely to be helpful, we may temporarily disable predictions or warn that they may be affected by an ongoing event, as a precaution.
How fresh is the information?
It's based on information that's pretty close to real-time. Our database is updated two or three times per minute. In most Web browsers you'll see arrivals update automatically about every 30 seconds.
Note: On your mobile device, we don't have it set to automatically refresh so we don't eat up your data plan. You can tap or click the "refresh" button to update to get the latest data from our servers, or turn on the ability to auto refresh by tapping "options" when looking at a set of arrival estimations.
Am I looking at a near-final product?
Not yet; this is a preliminary release at its second big milestone. We still have a few more features we're working on, and some improvements to the information this service can provide. We're also listening to what you have to say and work that into future versions of the service.
Why does the order of trains at my station sometimes change?
The ‘L’ is a complex rail system with hundreds of miles of track and dozens of track junctions. Estimated arrival times are just that—estimated.
CTA Train Tracker is designed to re-estimate arrivals as a train progresses along its route and update its predictions based on the latest information available. At stations near junctions (such as in the Loop), when trains approaching your stop are coming from different parts of the system, you can expect to occasionally see the list of estimated arrivals reordered, based on the latest real-world conditions.
Why doesn’t CTA Train Tracker tell me if a train is running express?
Right now, this information isn’t available to the Train Tracker system. We’re working on building it in, though, so you’ll better know what to expect wherever you are.
How do I set or un-set a favorite stop?
Simply click the star next to the stop name when looking at a stop in Train Tracker on our Web site. This works both on desktop computers and most mobile devices. The star will go from grey to gold if selected. You can de-select favorites by clicking the star to make it grey again, anywhere the star appears.
Why did my favorite or recent stops disappear?
We don't store favorites or recent stops on our servers. Stops you've recently viewed or flagged as a favorite are stored using a "cookie" on your computer or whatever device you use to view our site. If you clear your browser history, including cookies, the information about what stops you've visited or "favorited" is cleared, as well. If you've set your browser to clear cookies every time you close it, or are visiting in a private browsing session, this information will not be stored.
How do I clear favorites or recent stops?
Simply clear your browser's cookies. Note that this will likely clear all information remembered by your browser, such as sites you've logged into and told to remember you.
Why does CTA Train Tracker tell me the train is going toward “Howard or Loop” on the Purple Line or “63rd Street” on the Green Line when showing scheduled arrivals, rather than a specific destination?
Because our expert field personnel sometimes need to make manual modifications to maintain good service on the system, scheduled departures on the Purple and Green Lines might not be as precise as a live prediction. CTA Train Tracker waits until the train leaves to announce a specific destination, and once it’s left the terminal you’ll see exactly where that train is expected to go. Remember, CTA Train Tracker is a work in progress; more and better information will be available in the future as this service is developed further.
Is CTA Train Tracker accessible to people with disabilities?
Yes, the CTA Train Tracker Web service is built on modern Web standards and designed to follow both established accessibility guidelines and best practices, to ensure that all people can enjoy the information provided using standard Web browsing software or with assistive technologies.
CTA is also in the preliminary testing phase of displaying Train Tracker arrival times at 13 rail stations on existing LED displays. Right now, we are working to verify reliable arrival time data transmission to the station signs. When the results of this testing phase are deemed satisfactory, the pilot will be expanded, including additional stations and accessible features such as an audible component. During the LED sign preliminary testing phase, visually impaired customers may call CTA Customer Service at 1-888-YOUR-CTA (TTY: 1-888-CTA-TTY1), 7:00 a.m. to 8:00 p.m., on weekdays (excluding holidays), to receive estimated arrival times.