Yes, it's interesting.

For commuter lines and Amtrak PTC is existential - given the lack of progress on it in general, unless the deadline is softened somehow there will be no rail commuter service in some big areas as of New Years Day 2016. Likewise Amtrak outside of the NEC. [conspiracy theory] Could the delay be Republicans in Congress seeing this as a way to terminate Amtrak and not caring about the collateral damage? [/conspiracy]

Other than Metrolink (LA), will any other commuter lines be finished with PTC by 12/31/15, even if just on their own tracks (the elephant in Metrolink's room of course is their use of BNSF and UP tracks for many runs)? With some of the big ones (like Metra) only recently advertising for contracts to do it, I wonder. And even with PTC is working on their own lines, if they also have freight service will there be freight locomotives properly equipped to run there or will local freight service have to stop too (cue the business failures and job losses)?

The freight service issue is big, but not everything triggers PTC requirements so I think the talk of a complete shutdown is fear-mongering. Railroads could park the offending loads in a convenient yard on 12/31, and leave them there until things are resolved. OTOH, with no Bakken moving, oil prices will skyrocket, and some other industries will crash to a halt too (chemicals? propane? some fertilizers?). I don't think coal trains trigger PTC, but if they do the lights will go out in some areas. How about intermodal? Could Congress or FRA allow non-compliant railroads to keep running passengers and targeted freight, but only at restricted speed (yes, I know, impractical, but...)? Time to sell railroad and buy pipeline & barge & trucking stocks (actually, too late!).

Anyway, I think you're right: the phone is ringing in congresscritter's offices already, and the message from Big Business supporters is not being expressed in pleasant language.