There warning system sucks if a train can travel for more than 20 miles with a sparking over heated axle and that problem is not quickly detected. In the days of cheap wireless equipment then how could it be that the entire train is not rigged with video cameras and sensors that detect this condition immediately. Especially when hauling such dangerous chemicals. The train company should be held criminally liable.
Probably a money issue. Not sure how profitable train systems are. I know that Amtrak has lost money every year since 1971, and many of the metro trains lose money as well. One would think that freight trains do alright, but not sure what condition the track systems are in.