The vote for the sick days was largely along party lines, with all Democrats in favor and only three Republicans crossing over. We'll see what happens in the Senate. Point is, there is a difference between the parties.
I think the sick days were the sticking point for the unions that did not approve provisional deal. So this reads to me like this:
Side with the megacorps - pass the first bill
Side with the 'economy' - pass both bills (temporary benefit for most workers)
Side with workers - pass neither bill, pass a new bill giving them higher benefits than requested to show rail companies that they can't play fast and loose with infrastructure and expect any support
From perusing /r/railroading, it sounds like they're okay with the outcome, if not overly enthusiastic. The real problem may be yet to come. The Senate still has yet to approve this, and Republicans can filibuster the bill that includes sick days.
Still though, the point remains that we wouldn't be in this spot to begin with if the critical rail road workers weren't being consistently nickel-and-dime'd by the mega-corp rail companies.