It will be some time, but we haven't thought about the details yet.
As you may know, we have work crews on call to address maintenance issues and mishaps. You can call the supervisor and ask him to send a work crew to do some work, but such resources are limited, and the workers are - of course - unionized. We are thinking about something similar for train crews, e.g. stand-by crews, that you need to send to the location where they can make the crew exchange. However, as some exchanges may be part of a regular schedule, there may be some variations right there.
These are ideas floating around for CTC. We will revisit TD3 to see how it was handled there. Personally, I have disabled the crew exchange feature there - it was not a favorite of mine - so I don't remember all the details. As you probably have noticed, we like to put our own spin on things, so the crew exchange will be a little bit different I'm sure.
We'll keep you posted.
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Detlef