So I'm thinking at 100 mph maybe 100-500 mile trips would be the target audience. Feel free to discuss the numbers.

Absolutely, the 500 mile and under midtown to midtown market (large population centers) is the prime area for train transportation.

Sure, but with perhaps a couple of caveats:

1) At the present "HSR" speeds in the US, like the Acela, and

2) Assuming there exist nonstop flights between the endpoints: if flying involves changing planes at an intermediate hub, the equation changes.

I made a little stupid model of when flying or the train is faster, as a function of distance. I made the following assumptions:

1) There is an additional time overhead associated with flying over taking the train, which involves everything from getting to the possibly remote airport to security to required check in times to the time it takes the plane to get from the gate to cruising speed. I "determined" this time by forcing the rail and air trip from NYP to WAS to take the same amount of total time, which has been demonstrated in the past to be roughly the case. The result was 2.5 hours of extra overhead time associated with flying, which at least is more or less consistent with reality.

2) The cruise speed of a plane is 400 mph. I just made this up.

3) The additional overhead associated with stopping at a hub enroute is two hours. I just made this up as well, based loosely on the many hundreds of hours I have spent in DFW and other airports over the decades.

Under these assumptions, obviously taking the train will be quicker for short trips and flying will be quicker for long ones, with a "crossover distance" at which the times are equal, with the crossover distance varying with train speed and number of airplane stops. We can make a little table of the results (I hope the formatting works!):

Crossover distance (flying is quicker if the distance is longer than this)

Number of stops enroute by air 0 (nonstop) 1 (stop at hub)

--------------------------------------------------------------------------------------------------------------

Train average speed 77 mph 240 miles 430 miles (77 mph is the average speed of an Acela between NYP and WAS)

100 333 600

150 600 1000

So, sure, 500 miles is about the right cut off with the caveats mentioned above. If we could build true high speed rail in the US, though, or if we were connecting non-hub cities with few or no nonstop flight connections, a longer distance might be time-competitive with flying. Memphis-San Antonio (625 miles by air, 727 by road), to pick a pair of random non-hub cities: 11 hours driving time, 8 hours flying (according to my assumptions above), but would only take six or so hours by 100 mph high speed rail.

So given higher speeds and non-hub cities, the threshold where air takes over might be significantly higher.

Ainamkartma