I think there must be a short-line railroad association out there somewhere. I'm pretty sure I've seen it. There are also short-line tax credits; not sure if they've been renewed this year. Although they are in some ways the "competition", I'd subscribe to Progressive Railroading Magazine.
From my observations, it seems there are not too many independents. There are a few holding companies out there: Rail America, Genesee and Wyoming, and so on. And, although it's not a Class III Railroad, FEC is held by a takeover specialist. You could also look at some of the Class II's such as Providence and Worcester.
And, you could make quite a few of us in the Northeast happy and buy Housatonic Railroad company.
Please keep us informed (of course, without violating any SEC or insider laws).
Next stop, Willoughby
~el Jefe ("Jeff Smith Rules") :: RAILROAD.NET Site Administrator/Co-Owner