Here is your statement again:
Supreme Court had to rule that way, or else more than a hundred years of precedent and government action with railroads, oil pipelines (which you support) blighted neighborhoods, etc., are all instantly illegal.
Kelo had nothing to do with railroads, oil pipelines, or blighted neighborhoods. So the decision had zero effect on more than a hundred years of precedent and government action. And why? Again, because Kelo had nothing to do with the examples you cite.
Instead, it was Kelo that overturned a hundred years of precedent. Because before Kelo, eminent domain was only used for public use. But with Kelo, government can take anyone's property away at any time as long as they can hope to derive more property taxes from the people they give the property to. And for some inexplicable reason, you support this.
Pipeline is entirely privately owned. There is no government ownership over the pipeline. There is no direct profit from Kelo, aside from increased tax revenues. It is "public use" in that it provides a public benefit. Public benefit is the reasoning behind Kelo, and also all the other court cases that preceded Kelo.
Kelo had nothing to do with railroads, oil pipelines, or blighted neighborhoods.
Yes it did; precedent used in the case was Bernan v. Parker, dealing explicitly with developing blighted neighborhoods. Hawaii vs. Makliff, similar, but dealing with breaking up a supposed land monopoly (a bad decision, but also used as precedent and even defended by O'Connor writing for the dissent).