There's a push in Washington to re-regulate the railroads -- and a powerful industry lobby is behind it.

The National Industrial Transportation League is lobbying for rules that would limit railroads' ability to negotiate for what they carry and at what fee. The Association of American Railroads opposes the rules.

NITL's members include Exxon, DuPont and Cargill -- companies that ship a lot of stuff.

AAR's members are the railroads, which is why I put Warren Buffett in this mix: His Berkshire Hathaway owns Burlington Northern Santa Fe railroad, a member of AAR.

So this the irony: Indirectly, you have Exxon lobbying against Obama fundraiser Warren Buffett -- and Buffett is on the anti-regulation side.

Also, it's another lesson in the general teaching: When you see a proposed regulation gaining steam, always ask which powerful industry stands to benefit from the rules.