I tend to agree with you regarding CEQA abuse. But many things have been done to corral that, such as time limits on filing lawsuits after a decision. NEPA doesn't have those limits, so in principle you could use it to stop a project under construction or even close it after it's open. As Jean-Luc says, that would be unusual, but it's theoretically possible. Of course, filing a CEQA suit against a state or local agency in state court is a common, relatively inexpensive operation compared to filing a NEPA suit in federal court against a federal agency - much higher hurdles on the fed side, and much much more expensive and time-consuming.

Sounds like the anti-HSR people need different approaches (not using CEQA as much), and will probably need to pay more attention to NEPA and STB in the future. That could get expensive ...