I have some published LCAs at home, but the gist is that most US studies:
-assume improving existing infrastructure instead of new right of way and new track, which limits speed to ~125 mph
-calculate efficiency ignoring embeded energy/costs (fuel per passenger mile, instead of complete LCA)
-are based on unrealistic track usage. At some capacity a track can't hold anymore trains and you need a second track, while airspace for additional planes is flexible and almost free. Also the faster the train, the further they need to be spaced out, which typically reduces capacity.
-price subsidies such that ticket price per passenger mile is roughly $0.45 rural - $0.55 Urban, which matches airfare for shorter flights, but not longer ones. (500+ miles)
-that pricing is targeted because it correlates roughly to the service window where time of travel is roughly competitive with air travel, taking into account check-in time.
-assume improving existing infrastructure instead of new right of way and new track, which limits speed to ~125 mph
-calculate efficiency ignoring embeded energy/costs (fuel per passenger mile, instead of complete LCA)
-are based on unrealistic track usage. At some capacity a track can't hold anymore trains and you need a second track, while airspace for additional planes is flexible and almost free. Also the faster the train, the further they need to be spaced out, which typically reduces capacity.
-price subsidies such that ticket price per passenger mile is roughly $0.45 rural - $0.55 Urban, which matches airfare for shorter flights, but not longer ones. (500+ miles)
-that pricing is targeted because it correlates roughly to the service window where time of travel is roughly competitive with air travel, taking into account check-in time.