I'm curious, how come Japanese locomotive hauled trains barely ever reach above 110 km/h? In Queensland they have 1067mm gauge as well and their trains can reach up to 160 km/h

The difference of them is number of windows and interior.
But you mentioned as that, they are very similar cars, especially exterior.
I plan rebuilding Suha 43 coaches, and add some cars.

What is the difference between this one and Oha 43? Weren't those also rebuilds of older cars?

This carriage looks really familiar where have I seen it before, I can't put my finger on it. OH WAIT, now I remember. I've seen this in a certain animated feature film from the 1980's featuring a train that runs, not on earth.
(Look if you get this reference hat's off to you).