Ride on Railways bogie wagons

I purchased two fully sprung bogie chassis from Ride on Railways. These have extremely low friction bearings and roll gently down the slightest slope. The chassis is designed to take removable drop on bodies. Ride on Railways can supply assembled coach bodies, but I decided to make an open and a box wagon out of 9mm plywood.
The plans are available as both TurboCAD and .gif files. A single 2440mm by 1220mm (8' by 4') sheet is enough for one box and two open bodies. The open wagon is a simple five sided box with the floor raised to allow a 20mm lip below which fits securely on the chassis. Two cross divides provide further rigidity. These are lower than the sides to allow the seats to slide up and down.
Three removable seats mean that three adults can just squeeze on as the wagon is around 25cm shorter than the Maxitrak wagon. The woodwork was brush painted with 3 coats of quick drying teak satin wood stain. The four corner braces are cut from 25mm right angle iron spray painted with Halfords automotive primer and satin black.
The box wagon has a similar construction but without the floor. Timber strips along the inner sides sit on the chassis.
Two cross divides provide rigidity. These are cut at the top to accept 33mm by 18mm timber onto which the roof is fixed.
Three timber strips are used to support the roof. The woodwork was brush painted with 3 coats of quick drying teak satin wood stain.
The roof is made of 2mm medium density fibreboard (MDF). This is glued and nailed to the central timber support strip, and then to the side strips. A lot of round head nails are needed to hold the curve. With the strong supports underneath, 2mm MDF is sturdy enough to carry adult passengers. Thicker board would be sturdier, but very difficult to bend to the curve.
The roof was brush painted with three coats of black satin which provides a durable finish. The box wagon is more comfortable for adults than the open wagon, though potentially a little more unstable with its higher centre of gravity.
Three years after completing the open and box wagons, I bought another chassis. It took me a further year to work out that the best use for this would be as a simple flat wagon for carrying loads and occasionally small children. The top is a piece of 9mm plywood with the same dimensions as the floor of the open wagon. The metal frame is 38mm deep so I added four timber cross supports of this depth to align the top and help distribute the weight on the chassis.
This view from underneath the chassis shows the supports.
As with the other wagons, I painted the woodwork with 3 coats of quick drying teak satin wood stain.
The body heights of the different wagons can be clearly seen here. The Trojan tram pulls the open wagon, flat wagon, Maxitrak wagon, box wagon and little red caboose.