As for a):
That might be true for a coast to coast flight vs. a coast to coast train ride. But most travelling is not that distant.
The population density in America as a hole is far smaller than in Switzerland, but the population density in NY State is almost double that in Switzerland. In fact, the population density on the US coasts, where most of the infrastructure is, is in the same range as in Europe. The cost of laying and maintaining a few train tracks over the sparsely populated US interior is not the reason it's more expensive in the US.
Railroads in Switzerland are built in extremely mountainous terrain with lots of expensive tunnels etc. and in expensive urban areas.
The population density in America as a hole is far smaller than in Switzerland, but the population density in NY State is almost double that in Switzerland. In fact, the population density on the US coasts, where most of the infrastructure is, is in the same range as in Europe. The cost of laying and maintaining a few train tracks over the sparsely populated US interior is not the reason it's more expensive in the US.
Railroads in Switzerland are built in extremely mountainous terrain with lots of expensive tunnels etc. and in expensive urban areas.