The most complicated 3d modelling software I ever used was Gmax, when I first checked out Blender I think it was version 2.5 or 2.6. I didn't progress to learn it further as there were no tutorials available for MSTS back then not even the exporter was available from memory "could had been an earlier version".. Anyhow, I decided purchasing Train Sim Modeler to make my models. This was a good starting point for me
I then downloaded and tried out a few other 3d modelling software, Google Sketchup Pro 8, 3ds Max, Maya, AutoCAD, Inventor, Sketchup "later versions" and finally decided that I liked Blender 2.78/2.79 then it updated to 2.79a following 2.79b and I was amazing with how quickly I learnt how to use Blender. As soon as 2.80 came along, alright I did download it it was confusing as anything because everything has changed.. Don't worry, I never gave up took until 2.93 to learn everything of the newer version of Blender
The last software I purchased was 3d Crafter 10 Professional by Amabilis, in early 2024. Late 2024, early 2025 the Amabilis website is disabled, but can be accessed via the web archive to download 3d Crafter 9.5 and 3d Crafter 10 including both version extensions. Purchasing 3d Crafter 10 Professional is obsolete.. Don't worry you can still export to Trainz, MSTS, BVE, RailWorks/Train Simulator using 3d Crafter 10 free version download from
https://web.archive.org/web/20240229154448/https://amabilis.com/
Also helpful if you have your old Train Sim Modeler DST source files, you can export into a different format or export them into any of the above games.
What really helped me to get more involved to learn Gmax and to learn more about other 3d modelling software, was because 2 Trainz members here on the Trainz forums Davido and NSWGR_46Class had provided their some 3d model source files. I will admit it was fun pulling the models apart and learning how everything came together, I also did the same for purchased 3d models and model source files I obtained from other authors or downloaded freely
This is how I learnt how to 3d model, as for creating textures I am still on a path trying to learn everything LOL