... Otherwise the wheels could move a fraction sideways in the gap, leading to rough running, and they may even strike the nose of the vee. Unfortunately some of your crossings are not properly checked (yellow arrows): 2_010945_560000000.png Here I am shortening the length of the flared part to make sure the V-crossing is properly checked. This flare length mouse action does not affect the overall length of the check rail. Each end of a check rail is adjusted separately by clicking the label (in this case DS1): 2_010948_320000000.png This is at real> adjust check rails... menu item. regards, Martin. posted: 2 Nov 2014 12:49 from: Julian Gascoyne Martin Wynne wrote: The wheels must be under full control of the check rail before they reach the knuckle gap in the V-crossing, i.e. they must be on the working part of the check rail beyond the flared end. Phil& Martin Thank you both for the advice. I now understand what the 'checking' is trying to achieve, a bit ...