... bolt in front of the nose. Another feature that struck me was the alignment of timbers at right angles to one or other of the routes through a crossing. That was the way I laid out my representations of North British crossings until I read Richard Chown's comments at topic 401 – see in particular point 10 in post #92. As a result of this I adjusted my designs so as to align timbers carrying A, B, C, D, X and Y chairs on a line drawn at right angles to the bisector of the vee. I did this in the expectation that the resulting skew of these timbers would ensure that the crossing chairs they carried could be mounted on them with ample timber beneath such chairs' mounting holes into which the fixings could bite. Taking this approach to a perfectionist conclusion, you might also need to adjust the spacings of timbers carrying special crossing chairs according to the flexure of the two roads beyond the crossing, a point also touched upon in Richard's commentary. Of course, my observations of North British practice may ...