Another thing to consider for discussing the NEC is that the Acela and NE Regionals should be considered different. One is for faster service aimed at business travel whose companies are willing to pay higher fares for faster and more convenient service while the Regionals are alternate travel more towards the regular average Joe. I'd be willing to bet that the load factor on Acela's is way higher than the NE Regionals and Acela's load factor compares more favorably to the LD's than the regionals.
I'm guessing Mr. Selden would be against the Avelia Liberty investment:
http://media.amtrak.com/wp-content/uploads/2016/08/NextGen-Fact-Sheet_Proof5.pdf.
If they are as advertised, you would increase capacity (perhaps the ability to lower fares and still increase revenue and increase the access to the regular passenger to take the route as opposed to the NER's) along the route, have faster and more frequent service. If Amtrak believes what Selden says then why would they spend money to increase capacity and frequency to a service that can't fill the seats now (that probably is true ... for the NER's). I'm trying to figure out the downside other than the obvious cost expense. Could you buy 28 Viewliner and/or Superliner sets with the same money and if so how much would that increase service when a train like the Empire Builder requires 5 (or is it 6?) per week now (forget the fact you have to fight the host railroads)?
I'm guessing many of you feel Selden is a train god but I do question some of his arguments. That must put me on the outside ... again. I'm used to it though and what's a newsgroup if everyone agreed with everyone else)?
Load factor is a dubious metric for comparing the business lines. Yes, the NEC's load factors are lower...but at the same time that's because Amtrak offers a more comprehensive timetable on the NEC (not to mention, they also basically have to run the whole train WAS-NYP even if a bunch of seats are empty south of PHL...early/late Acelas, I'm looking at you).
As to the cost of the Acela IIs ($2.45bn, presuming that the whole package associated with them is considered part of the purchase), that would fund about a thousand new single-level railcars. Using a trainset model for this (even if they would be individual cars), let's say you want your "standard" LD train to be 12 cars (bag, 4 sleepers, diner, cafe, 5 coaches)[1] and two locomotives. Per Amtrak's estimates from a few years ago that's going to be $2.5m/car and $5-7m/locomotive (so $40-44m/set). That's 54-61 sets.
Right now the LD system uses something like 52-53 sets of equipment plus spares (I forget how many the Sunset Limited uses), so in theory you'd be able to increase LD service by somewhere around 100%, maybe a hair more if you were then able to use those frequencies to improve equipment turn rates (e.g. reducing the amount of equipment that sits idle for close or more than to 24 hours somewhere). My guess is that you'd be able to roughly get a 110-115% increase in service.
To be fair, there's not a strict apples-to-apples comparison here given the nature of some of the Western LD consists but you'd suddenly have a ton of additional LD capacity. Still, you'd probably be looking at ridership on the LD system coming close to doubling...maybe more, maybe less depending on the schedules that you opted for as a result (and any knock-on effects to other schedules and through-traffic). Still, that's probably somewhere in the ballpark of another 4m riders give or take.
Edit: If a mass order like that knocked the unit price of the cars down by 10% that's $37-41m/set that's another five sets. At $2m even (20% down) that's $34-38m/set and 64-72 sets (10-11 additional).
[1] Obviously there would be variations: The Silver Star presently runs with 7-8 cars and a single locomotive while replacing the Builder with single-level equipment while preserving present capacity would probably involve something like a 15-20 car train (I'm thinking 6-7 sleepers, 7-9 coaches, and 2-3 food service cars). You could also stipulate that on some routes with multiple long-haul trains there would be one or two "A trains" with a diner, second cafe/lounge, and more sleepers and one or two "B trains" with just an enhanced cafe and fewer sleepers. Playing with the Builder as an example, a Western Star/Mainstreeter running with more limited amenities on an alternate schedule would arguably cover many of the same riders...but should induce additional riders as well through the added convenience of a second daily train. In this respect, two 12-14 car trains might well perform better than a single 20-car train in terms of attracting ridership, even if one of them is obviously the "lesser" of the two.