Why have conveyor belts instead of having more freight trains?
Also it's apparently something they do. "And it’s not totally untested. The country’s Torigatayama limestone mine uses a 14-mile (23 km) belt, and in Africa a 62-mile (100 km) system moves phosphate between mine and port, SCMP notes."
Personally I'd think it'd be easier to make a canal but I'm not a civil engineer.
[1]: https://en.wikipedia.org/wiki/Japan_Freight_Railway_Company#...
Cargo ships would be high bandwidth, high latency.
For example, I think trucks would be better for perishable goods.
I suspect the real answer here is that the report was just some exploratory thinking, and unlikely to really happen.
It seems to go from a single boatmaster to crews of less than 10. The smallest container ships for inland shipping are about 30-ish containers; the largest about 500.
A truck can do 2 containers with 1 driver.
So, an inland ship can do 15-30 times as many containers per crew, compared to a truck.
That's irrelevant. The shinkansen tracks cannot be used for cargo trains: they're exclusively for high-speed passenger trains.
You can't share tracks between slow cargo trains and high-speed passenger trains. Not only is the scheduling impossible, but the cargo trains would ruin the tracks. The shinkansen tracks require frequent and thorough maintenance to keep them at the level needed for reliable high-speed service.
If you want to see what happens when you try to share tracks between cargo and passengers, just take a look at Amtrak. It's a complete disaster.
Sometimes I think ideas are published so that people in forums such as HN can come up with better solutions that they then learn from.