Choo Choo Pictures??

[H60MTI]

Is there anything that shows what the trains look like before I just randomly add them and start a mission to see?

[razo+r]

What you can do is place down a static object of the cart what you want to add, as this allows you to see what that object looks like in the editor. Other than that, no, there is nothing to show you what your whole train looks like in the editor.