Well, I have to say I like the idea of a internet-based railway series and have debated creating one many many times. With all these constructive critisisms (which is what I feel can help improve a show) I would suggest talking to people who've managed to make it work.
I find that Trainz would be the easiest to make, as it seems to be the most user-friendly programme compared to MSTS and Railworks 2. I know people you have made series' in the other 2 Rail-based games or 'simulators'. I would suggest looking at the works of 'gyjg6564167' with his 'The Full Bucketniers' sereis in MSTS or 'Rhysicus' series 'Over the Hills' in Rail Sim and Railworks, both of who have different angles on what makes a rail-based web series good, so I'd suggest watching the series' in order, to see how they improve them, the later of which released an OTH movie which, if watched from start to finish goes for a proper feature-length time of about 1.5 hours. It's just a matter of how you structure your story. Work with other writers, explore new camera angles and technics, anything to improve the performance of a series, regardless of the tools you are limited to.
I say that you should incorporate peoples comments in an effort to improve it, because, hey, we all have to start somewhere. Also, to keep it interesting, try to keep it real, don't make it all 'Thomas and the Magic Railroad' crap which in my mind ruined the fasination of the fact that the Island of Sodor could exist as a real place. Tycoon4 has some good points, it has to really be a journey that people can relate to, and its a matter of developing the skills you use to create it. It's not something you have to do, it's something you want to do so it pays to think ahead.
I'm very happy to help out with this, being a writer as I have studied film theory and so maybe some imput from those with expereince can help.
Anyway, theres the essay I didn't expect to write, but should give you some 'Food for Thought'
Cheers
Timo