

That would seem to allow an exchange of the content being referred to as long as it was for non-commercial use. You may share the Software Product with family or friends, provided they accept the terms of this EULA, but you may not sell or otherwise distribute the Software Product in exchange for monetary or other value or in any commercial manner. Personal Use: Subject to the following, you may use, edit and modify the Software Product solely for use in Microsoft Train Simulator and limited to personal, non-commercial use on your home computer. The only thing that I could see that might give a way out was this statement from the 'Content EULA', but I'm not certain, does this just apply to the additional content download that was available later?.

While capable modelers can certainly replace the MSTS items with original ones (for instance, I have a 'catalog' of different switch sounds that could be used to replace the often used default sounds for locomotive cabs), still, it would mean that those items wouldn't be useable by someone without MSTS.
