Why not another project?

Quite a long time ago (last decade) I brought a Trackgang UC-15 tank car as a start on a model of the well known tank train that ran regulaly between Wellington and Palmerston North last century. It has resided in the unmade kits pile untill I spied it a couple of weeks back and brought it out onto the workbench.

While theres really not a lot to it I think what had put me off a bit was mention of drilling holes in aluminium tubes and cutting to exact lenght etc etc. Holding it up to the plan it was 1mm over, so I imediately felt much better about not cutting it. The ends were glued on and sanded to tidy them up. And then we stalled. Not for the normal reasons of lazyness, but to somewhat expand the project. On my list of wagons that I came up with over a decade ago, I've got listed 12 UC15's and 2 Uc 4's. making them in metal is going to take a long time, and also a fair bit of money going to Russels model empire. What are the alternatives? 

At this point everyone would leap forward and cry "why not 3D printing?". Well, I'm not everyone fortunately (or unfortunately, its all a matter of your frame of reference). Being a bit more of an analog kind of modeler I've come at it from another direction.

16mm wooden dowel cut to length with the ends sanded to shape. sides sanded and a coat of paint on. Underframes cut from 2mm plastic to size with areas to grind out so that the wheels don't rub. Theres not a lot to the rest of the model that I can't do though I am going to need some brake cylinder's and ladders. I have a pile of old bogie castings sitting in a box and just need the wheels which are another issue. The bogies are brass castings that take US length axles ~14mm (not the UK 15mm). I look to be stuck with the 36" microtrains metal wheels at 5.5mm diameter (too small). If anyone knows where I can get US 40" wheels "at a reasonable price" I'd love to know.