rodclarkeca Posted February 16, 2013 Share Posted February 16, 2013 I am currently building some GCR bogie Fish Vans in 10mm scale and have a question about the brake rigging. I have some good Works drawings which show the operation of the central hand brake mechanism, the vacuum cylinder, and their interconnection. The two vacuum cylinders are disposed asymmetrically on each side of the longitudinal and lateral centrelines, i.e. diagonally opposite one another, and it appears that each vacuum cylinder operates only on the brakes of one bogie. The cranks which operate the rodding between the brake shaft and the bogie are disposed about 1ft to the side of the longitudinal centre line respectively, directly under one of the longitudinal chassis girders. No further information appears on the drawings, except faint lines which show that brakes were clasp brakes operating on both sides of each wheel. That is, there are 16 brake shoes per van. There is a similar arrangement on the GCR Barnum coaches at Ruddington. If the brakes were conventional I should simply angle this rodding towards the centreline in order to connect to the bogie brake mechanism. Unfortunately the clasp brakes have a very different arrangement. There is a mechanism disposed about each axle of the bogie, which uses cranks connecting the two triangular brake beams, one on each side of the axle, to pull and push all four brake shoes. There are two of these mechanisms on each bogie, and they appear to have long operating crank which sticks out above the bogie frame, to receive the operating rodding. My photographs of the Barnum arrangement shows that the triangular brake beam is symmetrical, and these operating cranks were disposed on the longitudinal centreline. They appear to operate in the same sense, i.e. a push or a pull from the central brake gear operates the clasp brakes in the same sense and physical direction on both axles. What I can’t understand, or see on my pretty detailed photos of the Barnums, is how the rodding gets around the bogie pivot in order to reach the outer axle mechanism. I can only see one operating rod approaching the bogie frame, but not what happens to it after it gets there. Is it possible that there were 90 deg reversing cranks, mounted on the channel section bogie girders in order to get the rodding around the pivot? Can anyone help? Rod Clarke Whitby, Ontario Link to comment Share on other sites More sharing options...
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