Answer:
Microsoft Train Simulator comes with the Train Simulator Editors & Tools program. Which in some terms means that you can "create" your train. BUT when i mean create i mean that you end up being able to pick a kind of train and add freight and/or passenger cars to/behind it. BUT to do that open up the Editor & Tools program and click ACTIVITY EDITOR then click File up in the left corner then click new the go over to PLAYER SERVICE and click new then a new window will pop up then click new and there you go! Have fun!