Soon after obtaining the plans for the Milner Hunslet, I decided not to build the tender as per the drawings, but to build a slate wagon instead. This would be used as a riding truck for this engine and the tram engine. It has space to add a tank if required for the steam engine.
I obtained some plans for a traditional slate wagon, which uses curved spoke wheels and a wooden body. Having got these, I then saw a picture in a book of some steel-bodied slate wagons. These are stronger, and generally use disc wheels. This made life simpler as I'd got 4x 5.5" disc wheels I'd had lying around just waiting for something to happen..... Also, I could make the body a bit bigger (to scale, the whole thing's only about 22" long which is a bit small to sit on comfortably)
I decided on a chassis size of 30"x14". I built this using 50x25x3 ERW rectangular tubing, which is relatively light for its strength, yet simple to cut. The chassis is held together by 4 pieces of 40x40x5 angle in the corners, secured with M8 bolts. It's overkill really, but it was what I had to hand.
The couplings are 2x 6"lengths of 50x25x3 ERW tube, with a slot cut out of the end, and hole drilled in them for the coupling pin. Functional, but not very pretty.
I took the disc wheels I had and dished out the centres, to make them look more prototypical. I also drilled 3 holes in each one, as per the photographs I'd seen.
I bought some light plummer blocks to use as bearings. These were ball bearing blocks - again, not very prototypical, but they'll last a long time and not need much maintenance. Having got these, I turned up the axles to suit them, the wheels and the frame width. I also cut 4x 4" lengths of 25x25x3mm ERW tube for the bearings to rest on, to move them away from the chassis rails.
All that remained to do was to add the side framing. This is built using some angle iron I rescued from a skip (about 35x35x3) for the corner posts, some 25x25x3 as the top rails, and some 20x3 strip at the side. The result is a reasonable slate wagon look-alike which is also functional.
In order to make driving easier, I added a rest for the drivers' feet using some 20mm square tube. This allows the driver, as required, to sit facing forward, or either side, by bolting a rectangle about 20"x14" on to the bottom.