Railroads in general have the right of eminent domain. It's how many of them have been built. One can argue about whether that should be the case - after all, few railroads carry mail these days, which was a major argument in favor of eminent domain for them (as "post roads") in the beginning. But under current federal and state laws they have the right.

Like public agencies and railroads, utility companies have right to use eminent domain even as private companies. If PG&E really wants to run that gas or power line through your house, they can after paying compensation.

Companies and agencies that can use eminent domain try to avoid it - it's expensive, time-consuming, and uncertain in terms of HOW expensive (can't really predict how the court and/or jury (if it goes that far) will value things), plus of course Politix. But as a last resort it's available. Negotiations prior to filing the legal action of course operate under that cloud.