Railraod Employees arent government employees but under the Railway Labor Act they can be fired for an illegal strike. Since Congress ( completely within thier rights) has declared a strike would not be legal then under the act the RR can legally fire the workers if the strike.
Can they be replaced is anyones guess.
This law is crap but it is the law
The railroad can fire them, yes. But how are they going to replace them? Depending on position, it can take weeks or months to train replacements. In the meantime, the trains still aren't moving. What then? And THAT'S assuming they can even find enough interested people. Unemployment is still pretty low, and a lot of people don't want to work. Especially in those conditions.
It seems to me that this is a great opportunity for the workers to take a stand and defy congress and the president. If they strike, and everybody else backs down, great. If they strike, and they start getting arrested and/or fired, the trains don't move and the problem doesn't get resolved. For the companies and the politicians, a wildcat strike situation turns into a "heads they win/tails I lose" situation.
This whole situation just goes to show that companies can bargain in bad faith if they have some reason to believe the government will waltz in and impose a bad deal on the workers. Why would you ever bargain in good faith if you believed from the start that the government will take your side anyway? "We don't need to negotiate, the pro-labor president has our back and he'll stop them from striking!"
What's the point of even having a union?