I remember that 20 years or so ago, when 3-D printers were first invented, it was announced with great fanfare that they would totally revolutionize manufacturing in the 21st Century, and that in short order, everything from your cars to pancake flippers would be made by 3-D printers.
It didn't happen. In my book, a real flop.
Good to hear that they may be of use in making train stuff!
My brother was doing 3D printing for his master's thesis back in the early to mid 90's. The technology is not new.