We have the same thing in actual England, our rail system was the first and now we have to live with tunnels and bridges not high enough for double decker train

We have the same thing in actual England, our rail system was the first and now we have to live with tunnels and bridges not high enough for double decker trains. Most of our railways are limited to 125mph due to lack of in-cab signalling rather than because of track curvature though, tilting trains handle tight curvature problems.