Japan is very mountainous, so any flat land is really valuable. The proposal seems to suggest to put the conveyor belt in highway medians or tunnels below roads

Japan is very mountainous, so any flat land is really valuable. The proposal seems to suggest to put the conveyor belt in highway medians or tunnels below roads. Using highway medians sounds like it should bring a lot of issues, but it's free real estate on grades a conveyor can easily handle. Running train tracks there probably wouldn't work as trains are more demanding than cars when it comes to acceptable grades and curves. If they go with tunnels the rationale of the boring company applies: the smaller the tunnel the cheaper it is to dig.