Here is a link to the company that says they have 100% share of the Japanese rail market. The rails they produce are in the 400 Brinnell Hardness range. Hard, but I get the feeling that a torch can cut them.
They are not from the planet Krypton:
World's highest-quality rail products
Reduction in total cost by being the world's hardest, straightest, and longest lived.
The highest degree of hardness in the world realizes a high degree of economy.
Our rail products boast the highest degree of hardness in the world, realizing superb life cycle cost.
Particularly, the "HE rail" has high wear resistance and high resistance to surface damage, making for long life and reduced grinding, which in turn realizes improved economy.
The highest degree of hardness in the world realizes a high degree of economy.
We can manufacture very straight rails in 150m lengths.
Our independently developed universal rolling machine enables us to manufacture straighter rails.
We can offer rails that have a high degree of straightness, such as rails for high-speed trains.
We can correct deviations from the horizontal axis and the vertical axis using our own universal rolling machine.
https://www.nssmc.com/en/product/use/railway/
Or is the DR rail system using some other rail technology not currently searchable from the Internet?