There are defect detectors on rail lines, "hot box" detectors [1] [2], that are infrared detectors used to observe and report bearing failures on a train. My understanding of the situation is that with the current rail labor configuration, railroad workers are only permitted ~90 seconds to verify the operational capacity of the wheelset on a rail car vs a previous average of 3 minutes.

Also, more importantly, someone at a railroad indicated "crews are no longer notified of the defects. The dispatch makes that call and then notifies the crew", which means train operators might not even be aware they have a dangerous car in operation (and the data indicates a bearing can fail outright within minutes of being observed as being "hot" [3]).

High level, this is a result of "Precision Railroading" [4], which is just a fancy term of running a railroad with just enough labor to continue to operate. Congress voted to prevent union railroad labor from striking [5], so what actions take place after this incident remain to be seen. The Purpose Of The System Is What It Does [6], and as designed, this system is configured to extract billions of dollars in profits from rail freight operations [7] while avoiding liability for any damages caused or labor costs that can be avoided.

[1] https://en.wikipedia.org/wiki/Defect_detector

[2] https://en.wikipedia.org/wiki/Hot_box

[3] https://doi.org/10.1080/23248378.2019.1636721

[4] https://en.wikipedia.org/wiki/Precision_railroading

[5] https://www.cnn.com/2022/12/02/business/railway-labor-act-fr...

[6] https://en.wikipedia.org/wiki/The_purpose_of_a_system_is_wha...

[7] https://www.cnn.com/2023/01/24/business/union-pacific-railro...