ETCS as prerequisite for Trains in a Timetable

As in the forum post by Dirk Bräuer mentioned, there is a need to define ETCS as prerequisite for a train next to "national systems".

• start of thread [http://www.railml.org/forum/ro/index.php?group=4&id=150]
• continuation [http://www.railml.org/forum/ro/index.php?group=2&id=260]

Please consider both possibilities for defining this kind of information, the train as a whole and the train part:

• timetable/trains/train/trainPartSequence/equipmentUsage
• timetable/trainParts/trainPart/formationTT/equipmentUsage

The ETCS aspect also influences "speed profiles" (see #41 (closed)), "infrastructure capabilities" (see #80) and a general harmonization of this definition across railML (#23).