Handling of references from <switchIL> and <movableCrossing> to infrastructure

During the review of a certification sample of an applicant we noticed that the current practice of referencing track elements from switchIL and movableCrossing is not sufficient.

The reference is provided at the following elements in interlocking: //switchIL/leftBranch/@ref //switchIL/rightBranch/@ref //switchIL/branchTip/@ref //movableCrossing/branchUpLeft/@ref //movableCrossing/branchUpRight/@ref //movableCrossing/branchDownLeft/@ref //movableCrossing/branchDownRight/@ref

At all these places in railML 3.2 and 3.3 a track as supposed to be referenced. As it turned out, this is not sufficient in order to fully communicate the orientation of the switch/crossing. This is especially true, when the crossing or switch is in the middle of a track.

To mitigate this we (@coordination.IL, @coordination.IS, @coordination.TT) decided to allow for references to the functional infrastructure in these places, in particular the netElement.

As for the upcoming railML 3.4 the allowed references will be reduced to netElements only, in order to make it easier for importing systems.

Steps to be taken:

1.) Update ReferenceRegister of 3.2 and 3.3
2.) Update Wiki Documentation of 3.2 and 3.3 for the above places
3.) Update XSD/UML Documentation of 3.2 and 3.3 for the above places to be released with the next service release
4.) Update ReferenceRegister of 3.4 to only allow netElements
5.) Update XSD/UML Documentation of 3.4 to only allow netElements
6.) Update Wiki Documentation of 3.4 after release to reflect the change that only netElements are allowed anylonger