A quick Google search yielded the following which you may have already seen. Four links.....all have discussion of Cold and Dark startups. There are others out there.
I'm sure a script change is in order and someone more familiar with that will have to speak up on how its done. Some of the posts out there say its not possible unless there is a cold start marker option in its coding, like some of the British content has. See the last link. One option mentioned is shut the loco down, save F2, and then restart the saved game, but that may be too lame for you when you want it to simulate the way it works in real life as close as possible (like I do).
Also the very next F2 you do erases the previous one. If you aren't saving periodically in game play, you of course lose progress if you derail or mess up a coupling. That makes that F2 idea a one shot deal.
Another possible option I haven't tried but, I just thought of is this. If you are familiar with scenario creation and the tools involved, go into the editor and make a copy of your scenario (so you don't muck up the original). Start the copy and shut down the engines and arrange it as you want the controls, and decide if you are in cab or out. When you have it exactly as you want it, do Ctrl F2 and save a rolling start. Close the scenario and reopen the scenario in the editor and tick the rolling start box on the bottom of the info box, save and restart the scenario. When it opens I bet it will be dead and as you left it. The reason I say this is that in creating and testing scenarios I have found that having that rolling start saved, then going in and modifying the scenario to say add a message or change a "go via" or such doesn't take, unless I untick the Rolling Start I had previously saved, it continues to try to run it as the saved game in the rolling start.
No promises and again make a copy of the scenario, add "cold start" to the name to differentiate it from the original, and mess with it. The original should not be affected by any of this, I believe. If it doesn't work you can delete the copy and still have your original. Good luck... and don't yell at me if it doesn't work
https://forums.dovetailgames.com/thread ... art.35254/https://steamcommunity.com/app/24010/di ... 7328561196https://steamcommunity.com/app/24010/di ... 548176525/https://support.justflight.com/support/ ... ario-maker