IIRC, railroads still have 'rank' over roadways, and commercial waterways (bridge openings) may be higher rank than either. Part of this is a legacy issue from how transportation developed -- ships > trains > autos. And some of it still makes sense when it comes to right-of-ways, the less-maneuverable get preference. It's easier to stop a car than a train and it's easier to stop a train than a big container ship.
A couple of years ago, I read that Vegas has a helluva train problem with its road crossings but it's not the railroads' problem to fix. Here, navigable waterways can force bridge openings that snarl traffic. On the 4th of July, heavy beach traffic met heavy boat traffic at some drawbridges and the boats won. The DOT finally negotiated with the Feds and got scheduled bridge-openings during peak times since it was primarily recreational boating.
