Here is some text from the kit instructions which you might find useful. Most of this was written by Tim Shackleton for me when he did a test build of the 4mm version.
In 1950 BR had built three experimental brick wagons on the chassis of redundant Medfits. They had four-plank dropside doors and steel ends and were not a great success – they soon passed over to the engineers. After this false start the first proper Palbrick wagons, designed specifically to handle pallets rather than loose bricks, were built in 1957 to diagram 1/020 as Palbrick A. Like all subsequent Palbricks, their bodysides consisted of removable plywood panels set in channel runners, with one fixed end and one incorporating screw adjusters so the palletised load could be clamped firmly in place. In the rush to grab a share of this lucrative traffic many improvised brick pallet wagons were pressed into service, mostly converted from Medfits and not always given separate diagram numbers – some retained their steel dropsides, others just the ends, and there were some fascinating oddballs.
Further new-build Palbrick types and diagrams were developed in the late 1950s to accommodate different sizes of pallets specified by BR’s customers. All, however, had 10ft wheelbase chassis and were vacuum braked. Some were rated 13T, others 16T, some had RCH underframes and others the clasp-brake pattern while the internal width varied from 6ft 6ins to 8ft 2in – in terms of outward appearance, however, the differences were not vast. The subject of this kit is the wide-bodied, RCH-underframe Palbrick B to diagram 1/024 built between 1957 and 1958 at Ashford works. There were 200 wagons to this diagram, in the number sequences B461997 - 462116 and B462447 - B462526. In 1959 BR produced a further 90 Palbrick Bs – B462707 – 46296 – with clasp brakes, which were given diagram number 1/026.
Tim
Here are a couple of photos of the wagon build as promised.
This one is the underside showing the brake gear and vac cylinder. The cylinder is from NMRS models and is called a Python wagon cylinder. It's not actually on his list of parts in the catalogue but he will supply it if requested.
This photo shows how the springs go together.
The buffers are also from NMRS. They are number ref F013 and they are in his catalogue.
Ian