By Steve Gosling
The club rolling stock at Creech is vacuum fitted and this has provoked quite a lot of positive comment. The new club ‘Hymek’ locomotive and the two being built alongside it are to be fitted to work these vehicles and, to that end, Alec Hadfield and Noel Whiting have very kindly volunteered to make up some of the equipment. Firstly, Alec has made up a control valve for each locomotive. These valves have three positions whereby the train pipe can be connected to the ejector to exhaust it to the atmosphere to destroy the vacuum or a central neutral position which maintains the train pipe at the desired pressure. This allows the brakes to be held in a partially applied condition for control on long gradients or simply gentle retardation. The valves are roughly 4” scale and fully detailed drawings are available.
Of course, providing a vacuum with a steam locomotive is quite straightforward as a simple ejector may be used. However, it is a different problem altogether with an electric loco. Noel has resolved this beautifully by converting three 12V tyre pumps to vacuum pumps by reversing the piston seals and fitting an extra connection on the pump inlet. These work spectacularly well and on demonstration, evacuated an already ‘empty’ fire extinguisher in only a few seconds. To control these pumps, he has made a diaphragm operated pressure switch which keeps the vacuum within 1”Hg range. These pumps are quite noisy so to put icing on the cake, Noel has made a silencer as well. This can be seen in the photograph.
Thank you, gentlemen, for your hard work. The next part is to get the bogie frames laser cut and that is up to me!