From the BLM’s Facebook page:
Desert Safety Tip: Visitors need to be careful when exploring the desert during our infrequent, but powerful summer rain events. Last month, Afton Canyon experienced a large flash flood during a one day rain event. As can be seen from the staff gauge readings located in the canyon (see below), this event resulted in a sudden surge of water through the canyon — almost doubling normal water depths over night. As captured by U.S. Geological Survey (USGS) monitors, this was a powerful flood event. In fact, this event lead to a derailment of a train going through the canyon at the time. So be sure to be careful when recreating in desert canyons during summer storms! Video by Chris Otahal, BLM.
Here is more about the train derailment:
https://www.trainorders.com/discussion/read.php?1,4351472
Source: BLM Facebook
thanks for the clarification, we edited the story to remove confusion!
Note that Afton Canyon and Acton are two different places, so this is not all one story. The BLM and trainorders.com stories are about Afton Canyon / the Mojave River in the East Mojave, but the ABC news stories are about Acton, which is near Palmdale.