What percentage of high-speed rail is elevated vs. at-grade?

With an oblique reference to this thread about high-speed rail proposed for California, I wonder how much of Japan’s high-speed rail is elevated, as compared with at-grade. It seems like at-grade would be much cheaper to construct than raised.

Are high-speed trains more likely to be elevated than conventional ones? If so, why?

As you near the congested roads near the city centers in Japan, you see that all the train tracks are elevated. The traffic is bad enough without having to wait for trains that seem to arrive every few minutes.

Japan is very mountainous – I don’t know the percentage, but from looking at maps it appears that a lot of the railway lines (of all types, not just high speed) go through tunnels.

I have no doubt that in congested areas, they are elevated. But how about between cities where there is nothing but open land? Are they elevated there, too?

Not elevated, just whatever is easiest based on the lay of the land. In flat areas it may be just laid on the land (surrounded by high fences). In hilly areas it may go through long tunnels. Of course grade separation with other traffic is strictly maintained.

For high speed rail you need a track layout that allows high speed passage. This means no sharp curves and also no very ‘convex’ sections of the track - as that tends to have the train fly off the track. Those requirements may not be able to be met on the ground and using a elevated track, or sections, could be a much cheaper solution.

Why can’t those requirements be met on the ground? And how could raising a track be cheaper than not raising it?

It’s not just have you have to avoid tight curves. Trains generally don’t do well on steep gradients. If the terrain is not flat, your choices are elevated tracks, cuttings or tunnels.

It is not impossible to meet those requirements on the ground, just potentially more expensive.

The ground normally does not allow for the track layout needed for high speed train passage without extensive modifications which would include cutting through hills, tunneling and creating elevated sections. If you raise the track up you have less tunneling (which I would WAG would be the most costly of all), less cutting through the earth (which removing solid rock = hard and costly), but more elevation.

Also you have private property, right of ways (such as highways/roads) and other such issues which it is sometimes easier to use the airspace above then try to deal with it on the ground.

Looking to Europe, the Eurostar from London to Paris is at grade except for one tunnel. I would think that you build as much at grade as you can, with tunnels and elevated track where it’s unavoidable.

AFAIk at least the main Sanyo Shinkansen between Osaka and Tokyo is elevated at least 10 feet the whole way, so small local roads can go underneath it. I’m guessing the sub branch Shinkansens would have sections at grade but I’m not certain.

The Eurostar (and for that matter essentially all high speed trains in France too) runs mostly on flat ground. Neither Southern England nor Northern France are famous for their mountainous landscape. Japanese trackbuilders might not be so lucky.

Actually the main line north from Tokyo to Sendai, Morioka and finally to Aomori is pretty flat because much of the line goes along the rather level coast. The Hayabusa Shinkasen “flies” up there in just over 3 hours. The distance is over 350 miles. Remember that the train does have to stop at about 4 stations and wait for passengers to get on and disembark. This “wastes” a lot of time.

If you go over to the west coast from Tokyo to say Niigata, there are many tunnels, curves and elevated sections because you have to go through the “spine” of mountains that runs up and down the country. This Joetsu Shinkasen is fast, but can’t reach the speeds that the Hayabusa can.

When I was in Japan, I used the centrally located city of Gifu as a base. (It also had one of the cheapest youth hostels in the country.) Armed with my Rail Pass, from Gifu I was able to go almost any where in Japan and make it back again by evening. I loved riding on the train. I never tired of the views of the countryside