Now I will begin this by saying that I was quite pleasantly surprise by the inclusion of the yard at Röderau on Riesa-Dresden. It not only gives the route another place to explore on foot, but is also used by some freight services that join onto the main line here, rather than starting or stopping at Riesa, and routes that have freight services go to and from a different destination than the usual A to B is quite rare in TSW2. But having said that, this section isn't perfect, and it has a rather big issue when trying to navigate one of the spurs coming out of the yard. Specifically, this one going towards Riesa: Now at first glance, it might seem that you would be able to walk that section just fine, and that is the case... …until you get to a signal located near the main line, as seen by another view on the map that I have labeled, and some images of the offending signal. Now what's the problem I hear you ask? Well regardless of what direction you are walking in, as soon as you get up to this signal, this happens....: Yep, you get this message and the game ends right on the spot, and this happens regardless of whether you are walking into the yard from Riesa, or you're walking out of the yard towards Riesa. This is such a baffling issue as like I've said earlier, it looks like you can navigate this spur with no issues at all. Now I will say that there are no problems with navigating the other spur heading towards Dresden (I mean, considering that trains use that spur, it pretty much has too) It's just this one that you will have problems with. But even with this issue, this yard is still an area worth checking out on this route if you haven't already.
This mod removes most invisible walls and all out of bounds triggers: http://www.trainsim.cz/?mod=article&showid=2499&query=
I remember the place, there is a gnome collectible nearby, it took me several attempts to get it. Something went wrong there and should be investigated. This place MUST be accessible even without a mod!