If I remember correctly, the Santa Fe ran two RDCs coupled together and ran from Los Angeles to San Diego on a midday run to and return from San Diego. Their demise was at the 90 degree turn over the Los Angeles River near Redondo Junction. Redondo Junction is where the main line from Fullerton, CA turns 90% to run along the Los Angeles River to Union Station. It is near Santa Fe's roundhouse. If I remember the newpaper accounts of the accident, the two cars tried to negotiate this turn at high speed, derailed and overturned. Future runs were made by conventional equipment.