I have a station next to a coal mine and a line that goes from there to an ore refinery. I also truck in ore to this station (by the coal mine) from an ore mine not far away. This means both coal and ore waits at this station. Running on the train line is a 4 wagon train. Wagons can carry ore or coal so this train often carries both at the same time. This is where I think there is a bug.
The train window says the train can take 16 units of coal or 16 units of ore. This presumably means each wagon can hold 4 units. This train will wait for a full load of any before setting off. I have however seen the train fill with a number of ore units (eg 4) then filling up to 16 coal units, meaning the train carries 20 units to the destination .
Does this mean wagons can actually carry 8 units, and if so why can’t I fill the whole train with 32 of one type of unit? Or is it true that wagons only hold 4 of any unit and I’ve found an exploit to double what a train can carry?