Should the FRA allow Amtrak to use lighter passenger trains?.

Amtrak has historically been mandated by Congress to do all sorts of things that it otherwise would not willingly do on its own (i.e. run long distance routes to nowhere), but they are currently working to get the FRA to remove a regulation that would reduce its costs for operations and expansion. More from Slate:

Amtrak is going to push to get the Federal Rail Administration to change the safety regulations that force its passenger trains to be much heavier than the ones used in Europe and Japan. Relief from this rules has three kinds of advantages. One is that lighter trains use less fuel and thus are cheaper to operate. A second is that lighter trains can accelerate faster, making trips shorter.