I'm trying to better understand the debate about the FRA safety standards. Seems that a lot of people on this forum and elsewhere blame them for making passenger rail equipment overly expensive. It also seems likely that the heavier rail equipment in the US reduces the fuel economy/pollution benefit of the rail mode. I'd like to find some background material on the history of how the regulations came to be, why they're different from those in other developed countries, etc. I'm looking for more technical stuff and balanced historical accounts, but most of the stuff I've been finding in web searches is either the FRA regs themselves or polemical criticism. Anybody have any pointers as to where to look?