One the first, its just a back of the envelope calculation, but the second map works with 150mph, effective trip speed. I expect the research triangle will be 1m+ if its not by now.

Indeed, the original spreadsheet that this was based on had 50, 100, 200, and 300. This diary was the result of the observation that almost all the 1m+ cities tied together at the 200mph effective trip speed.

Politically, I think that's 66 Senators (68 if Denver CO could be included, but that's just at the edge of the limit on the Kansas City side, which is why it drops down to a dashed line in the second map) and a very large nuumber of House Seats represented. I think, consciously or unconcsciously, that's one of the reasons that the map attracted such attention on dKos. The standard is to think of fast rail for California and for Boston/DC, and the rest of the country gets nothing.

On whether the "1 hour" trips would really be one hour trips, if the vehicle was operating at a speed that allowed the "three hour trips" to be finished in three hours ... I don't think so, but I pulled out the sub-one hour legs anyway. For example, Cleveland/Columbus/Cincinatti if implemented with tilt trains can readily include Akron, Canton, Newark and Dayton enroute, plus a couple others (the main thing is to run through Columbus on an East/West alignment), and would plausibly be less than 4 hours end to end. So I pulled those out.

So its mapping the market, not mapping a particular technology.

On Houston / NOLA, I had it in, I'll probably put it back in. I took it out of the spreadsheet for the same reason as San Francisco / San Jose / LA ... but I'll put it back in next time I look at this. On NOLA / St. Louis, I think I just overlooked it (thanks).

On NOLA / Jacksonville, Jacksonville was not 1m+ in the 2000 urbanized areas data that I used, so it was not in the first map at all. I added it on a dashed line in the second map for the link that would be most attractive in Jacksonville itself.

In the added material on the end, which more reflected some of the concerns of the dKos commentary that I didn't want to write 50 identical replies to ... on the interstate alignment, I would not be surprised if it was preferable to run in a shallow trench in any event, to reduce cross-wind profile, so if a dive requires braking, I'd say stretch out the dive so that it doesn't. And I should stress more that this would be for the long stretches between urban areas, the Interstates are a lot more bendy when they get into areas that were already built up when they were constructed.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.