NBN EN 13232-3+A1:2011

This part of this European Standard specifies:
- characterisation of wheel and track dimensions;
- geometric design principles for wheel guidance;
- design principles for wheel load transfer;
- deciding whether movable crossings are needed.
These are illustrated by their application to turnout components:
- switches;
- crossings;
- check rails.
but the principles apply equally to more complex layouts.