Dear Dominik and Mathias,
thank you very much for your input! Taking the idea with the angle and applying it to the example from above, this may look like this:
<crossing id="cro42">
<name name="69K08" />
<spotLocation id="swi42_sloc01" netElementRef="ne_15" ... />
<crossingAngle fromNetElement="ne_15" toNetElement="ne_16" value="140" />
<straightBranch netRelationRef="nr_a15a18" radius="0" />
<straightBranch netRelationRef="nr_a16a17" radius="0" />
</crossing>
Does this fulfill your needs?
Best regards
Christian