Courts are supposed to weigh equities, but afaik they can't order you to violate the law.

Where in the Constitution does it say that common carriers subject to regulation must haul things that they are forbidden to by law or regulation?

Congress is the party that ordered the RRs to have PTC in order to carry passengers and TIH, and set the deadline without significant input regarding methods and feasibility in that timeframe. FRA regs fleshed out how that would work, but didn't change the law. If STB says anything other than their precedent (situations where embargos are OK, including this one) then FRA and the RRs should sue THEM.

Yes, absent some kind of reasonable action by Congress (how about: extend the deadline after hearing again from the RRs and FRA how much longer it actually will take, and why, and move on) we're looking at a major economic upset around the first of the year. Say, Dow drops to 3000 on Jan. 2? Can't drop to zero - several components have major offshore activities that will still produce revenue - but any company that makes things in the US will be essentially out of business on Jan 2 without railroads moving TIH, and believe it or not there still are a few.

For you California haters: $20 gas isn't impossible there w/o rail. Can still get the crude by sea for the big refineries, but not the ethanol at least on short notice, and the ethanol has to be distributed inland somehow.

Suggestion: if Congress doesn't act, the power company in DC should pull the plug on the Capitol and Congressional offices on Jan 1. No fuel, right? Let them yell at each other by candlelight (after fuel runs out for the generators and can't be replaced).