... how necessary is it to have prototypical gauge widening? – as wheels in 00, EM and P4 have a narrow back to back relative to the track. In P4 we have the best part of 0.2mm more clearance than the prototype, and the flangeways are widened by 0.1mm each side. Only S4 has supposedly prototypical clearances, and even there people seem to use the 30mm tool. My personal approach is to use the triangular tool and use the C&L gauges when I know I want a particular widening in pointwork. 3591_071503_160000000.png The blue line in the graph shows what the 30mm tool does. It gives nowhere near the prototypical widening at 4'9", but can be used down to a radius of less than 500mm before it's giving too much widening. Below is a spreadsheet that gives the same information as the graph 3591_071503_500000000.png 3591_071509_260000000.png Hopefully Martin will correct anything he considers erroneous. Attachment: attach_3172_3809_snip_GW.JPG 93 Last edited on 7 Nov 2020 20:17 by Julian Roberts posted: 7 Nov 2020 23:49 from: Rob Manchester Hi Julian, Thanks again ...