Wagons and bogies

The Pechot wagon is a rather large steel well-wagon which has been eating welding consumables for a number of weeks now. Quite a number of weeks, actually. Designed by the eponymous French engineer, these wagons were built in quantity for the French military before and during WW1. Quite a few survived, and can be found on many of the 60cm heritage railways in France – frequently converted into coaches. The wagon at Apedale had suffered a tough post-war existence at a concrete works, and had lost a lot of its fittings. These have been remanufactured and re-fitted. It is probably fair to say that the team working on it were getting a little jaded after fitting the nth stanchion pocket – BUT it’s finished – the last weld has been made – there is no more (shares in BOC will plummet at start of Monday’s trading…). The wagon has now been lifted off its bogies and upturned to allow the underside to be properly painted. Comparisons to a freshly swatted dead fly were voiced at this point. However, with the bogies out, there is chance to admire their engineering elegance. Particularly noticeable is the compensating lever between the two axleboxes with a very unusual centre pivot. This was a characteristic of M. Pechot’s design, and means that if one wheelset drops into a dip, the load is transferred (in part) from the other wheelset. This has the effect of making the wagon less prone to derailment on bad track.
Compare this to the brutal simplicity of the ex-South Africa three-piece bogies which are for FR coach 117. Work has now started in earnest on these. None of the engineering elegance of the French bogies. These bogies have two socking great cast steel side frames which carry the wheelsets, and these sit on spring packs which support the bogie bolster, on which the vehicle actually sits. A grand total of eight bolts hold the thing together – but all the side frame mass is unsprung. If you are a railway civil engineer, and have been upset by the site of a three piece bogie exposed in such a blatant way, please feel free to get in touch with someone.