The CTA had found during testing of the 5000-series railcars such as those involved in the collision, the cars' wheel slide protection system tended to continuously deploy the track brakes ...

The CTA’s 5000-series rail cars, two of which were involved in the crash, include a wheel slide protection system that was normally effective but tended to deploy track brakes “which could ...

The company has provided an APS solution for the Chicago Transit Authority’s (CTA) 5000 series cars. The challenge was to design a system that would perform reliably under varying weather conditions.