Page 15 has outlined some of the restrictions on railway rolling stock and speed, that are caused by FRA regulations
Due to the quality of regulations, the state of the art in tilting train usage is not available in the USA. The FRA safety regulations do not allow safe operation of trains at very high unbalanced superelevation, because the resulting trains are too heavy for that.
There is an ironical aspect in this result: Lightweight tilting trains have been a US development, and predated European or Japanese revenue service by 20 years. You can find the arguments of this text in the dusty part of archives in the USA.
The FRA regulations have the following impact on state-financed infrastructure upgrade projects for passenger rail:
- In order to achieve a given running time on curvy track, much bigger curve radii are needed, at considerably higher capital investment.
- Many upgrade projects are made impossible, because the necessary curve straightening does not fit into built-up areas.
Building passenger rail track with steep grades, a common cost saver in other countries, is
- not available in the USA, or
- punished with high operating costs.
It needs to be stressed, that there is a difference in US regulations, but no difference in US engineering. In 2002, the California Highspeed Rail Authority published a study about route options between Los Angeles and Bakersfield, that showed the same cost savings for the 3.5% options, that have motivated other railroads to use steep grades for highspeed lines. (At this point, there used to be a link to the report, but it is no longer online.)
For passenger rail in the USA, a higher quality of regulations would mean a multi-billion dollar value, if the policy is pointed towards improvement and extension of rail service.