... Wynne donald peters wrote: in the way that the form changes in 'steps' as the length changes Hi Donald, I think you are referring to the switch size changing as the V-crossing angle is adjusted with the F5 size mouse action? Unless you have set a custom switch, Templot changes the switch size in F5 to get the most likely prototypical match to the crossing angle. The well-known list of bullhead standard leads* is on the Clag web site at: http://www.clag.org.uk/protodata-bullhead.html You can see that there are a lot more possible crossing angles than switch sizes, so the effect is a step jump in lead length when a small change in the crossing angle causes the switch size to change. You can prevent the switch changing by right-clicking while using F5 mouse action, and then selecting lock switch on the pop-up menu. The colour of the descriptor bar in the information panel changes to pink to indicate that the switch size is locked. In this way you can try the less ...