I know it is not an answer to the original question but I just like old drawings and other ephemera, so here is an illustration from the original spec:
And some wonderful copy from same, just in case anyone is interested:
Each pair of finished wheels and axles to be properly balanced, and they must be driven at a speed equal to 60 miles per hour and show up perfectly true.
The wheels to be properly bonded with three strand copper wire where shown on the drawing for track circuit signalling, and all joints thoroughly coated with an anti-corrosive.
The Contractor shall provide, at his own expense, one additional tyre and one additional axle out of every fifty, to be selected from the bulk by the Railway Company's Carriage Superintendent, or any person he may appoint to inspect and pass the work, and to be tested in his presence by the Contractor in the manner hereinbefore described.
Nearly one half of the finished wheels manufactured are found on testing to be out of balance, even though every care be taken, owing to the density of the material, and in practice weights differing up to 2 lb. are necessary to be attached near the periphery to give required balance. These weights are in plate form and placed under the retaining-ring bolts as shown at B in fig. 338, or screwed to the teak centre just below.
Pete.
