I started with Railworks (well Rail Simulator as it was then called). My problem with Trainz is this - I have asked numerous sources including the developers why with Blender my animated content comes out black when placed in Trainz. I have posted an entire thread and bumped it several times with no solution provided. Since I developed some of my own content for RS and was going down that route before I got Trainz I could go back fairly easily. I do believe the development of content for Trainz is easier. However, this animation issue has not been given any input by the developers and no solution has been found for it. I feel I can't move to the next step in developing content without this being fixed. I've made animated cargo ships, graders, cranes, backhoes, planes, animated people - all when placed in Trainz end up black. All undermining my desire to develop content for Trainz.
I understand your position because I don't have some blood tie to Trainz or fanaticism.