Rail workers wanted to strike. There's a law allowing Congress to prevent that to avoid a catastrophic disruption to the economy - and it would be catastrophic. They voted to prevent a strike and Biden signed it. This was IMO a smart move, deliberately tanking the economy would have been good for nobody.
There was a separate vote to force the companies to agree to some of the workers' safety and working conditions demands, which Republicans blocked.
Place blame where it belongs.