A couple of years ago (though it seems like only yesterday), I made a 1:25 scale goods van on 24 mm track, for 2 ft gauge:
See here: viewtopic.php?f=18&t=10699
This seemed a bit big to me, so I made three more goods vans in different scales and gauges to see how they looked, and to try out different ways of making. My first wagon is on the right:
I really wanted something that would run on 16.5 mm track, but if the wagon was big enough, the wheels were so close together that the wagon was unstable. So I’ve decided to stick with 24 mm track, 1:25 scale but use a smaller prototype than my first wagon. On the se lounge I found several drawings for goods vans about 10 ft long, 5 ft wide and a bit over 6 ft high. Also here, second drawing down: http://www.009.cd2.com/history/goods.htm. This model is second from the right above.
I’m going to make another...