... -joint mark shown at the end of the switch rail. Frequently these coincide, according to the prototype data entered in creating the custom switch. In some prototype designs the heel data refers to a virtual heel some way short of the physical rail joint, and in this case these two positions do not coincide. The rail joint mark shows where the switch rails (points) would be hinged in a loose-heel switch. Whether you model it hinged or flexible is up to you. Here's a diagram showing that: switch_marks.png In some designs the loose heel occurs between the timbers, using a loose fishplate design. In other designs the loose heel is combined with a heel-block chair or rail fixing, and in that case it occurs on a timber centre. If you are modelling with overscale flangeway gaps, it may not be possible to have a working loose-heel in the correct prototype position, because there would not be sufficient flangeway clearance behind it. You then have the choice of extending the switch rails and moving the hinge position ...