It is nice to see this engine. I have to admit that I have myself been a little tardy of late with building stuff, so something like this maybe just what is needed to reawaken the bug.
I look forwards to seeing some of your PF models. Are they going to be in the normal 'L' Gauge or of a larger type? It would be good to see something in the normal scale as i find it easier to imagine the scene as a whole with some minifigures but each to his own and that does not detract from your build.
As for the awful use of NON standard parts like the BBB wheels, well, what a terrible crime to make on a LEGO forum!!! And Gluing parts!!!! Well, don't worry, I am sure all is forgiven, I have myself along with several other people on here used many a BBB Wheel for our MOCS, there are not many NON LEGO parts that are acceptable but I think you wold be hard pushed to find someone who would criticize you for using them. They are one of those few almost LEGO parts that seem to have become acceptable. Gluing, not so much, but I cannot deny that on occasion I have had a bit that for whatever reason has just become loose and will not stay in place. I should not do it but I may have resorted to glue once or twice, but don't tell anyone!!
Thanks for posting.