Just what it says, freight trains happily rolling along with gaps where cars should be. No, not empty container flats: nothing there at all. I tried to get a picture but for some reason Ctrl-F10 wasn't working.
You should use F12 or ctrl+F12 for screenshots. and specify the service/scenario you try to play. Also play it twice, to make sure you can reproduce it. F12 makes a steam screenshot, ctrl+F12 a DTG screenshot (saved in the images folder). F10 makes a dtg screenshot, which is rather useless at the moment.
I think you got enough options to create a pic. You also can use the standard Windows picture editing apps (I do not know which name the game it in English) to reduce the resolution and size.