Plot: Why did a 72 oil-car runaway train crash, killing 47 people and levelling half a town? Was it the brakes? Also, can engineers do anything to fix a gaping sinkhole at the National Corvette Museum, so car enthusiasts can safely return? And, what caused the Minneapolis Metrodome's iconic roof to collapse? Was it an engineering flaw or Mother Nature? Football fans want to know. Then, as 33 Chilean miners await their ultimate fate, trapped almost a half mile underground, mine drilling engineers scramble to dig a hole big enough to rescue them