Newark is the transit hub of NJ, with NEC and PATH service at Newark Penn, the Hoboken lines serving Newark Broad Street, two lights rail lines and tons of bus routes. Plus an international airport. If transit access matters to Amazon, Newark has got to be at the top of the list. Plus, it’s subsidiary Audible already has its HQ in Newark about two blocks from Newark Broad Street Station. The non-union status of Amazon is anon-issue in NJ.
Ahhh, no. Facebook still needs servers geographically located at datacenters near exchange points on the Internet to keep it's service snappy when you pull it up. It's still renting space everywhere. It may move it's background processing to Los Lunas where they paid out the butt for numerous fiber optic connections to the nearest network interconnect, but it make no sense to add another second of lag just to move equipment out to the middle of nowhere.
Think about it this way -- if you're a stock broker, you need to be at the action so you can respond quickly. You're ether on the floor or you have computers so close by that when you sell, it SELLS first.
Amazon's the same way. It's online stores and virtual server hosting (AWS) need to be close to those exchange points all over the US and world. HQ 2 would really need to be where it can connect to those exchange points. Guess where those points are?
Boston, New York, Newark, Baltimore, DC, Chicago, Atlanta, Tampa, Dallas, LA, San Francisco/San Jose, and Everett (near Seattle).
New York and Newark are closest to a ton of major businesses with international flair, so HQ2-North should be close. DC is were the seat of government is, and HQ2-South would share space with Amazon's lobbyists. Those are two MAJOR benefits that the others don't have (Amazon's HQ1 being in Seattle). Chicago is "close" with it's mercantile exchange... but that's it.
The only thing here is for Amtrak to be "up to it" is that there is fast enough service between the two HQ2's to render flying moot. Amazon's HQ2 south will be Crystal City. If HQ2 North is along the NEC, then Amtrak is "Up to it." If it goes to Chicago, then Amtrak is "not up to it" and it needs to build a high-speed rail service between Philly and Chicago via Pittsburgh real quick.