... to a "joggle" is of course to file away a bit of the inside face of the stock rail to provide a bed for the switch rail to fit into. Particularly useful in smaller scales where there are limits to how thin you really want the switch rail tip to be. Hi Nigel, Only the extreme top corner needs to be a knife edge. The rest of the switch blade can be quite robust at the tip. This is a simple model approximation to undercut planing for use with a plain set: 2_010801_470000000.png The switch blade needs to be reasonably robust at the tip in model flexible switches so that it opens to a full flangeway clearance all along its length. If the tip is too thin and fragile, only the end section will flex to the open position. If you adopt a filed "joggle" it is important not to make it a sharp notch. Wheel flanges can catch on this on the open side when running in the trailing direction, especially on curved turnouts. This is a prototype objection to joggles too - ...