TL;DR
Implement a hotkey for switching trains from [Automatic] to [Manual] and vice-versa, that when clicked whilst the mouse is hovering over a train, switches this condition.What ?
Literally just that, or allow hotkeys for setting the condition of a train to [Automatic] or [Manual] rather than a switch.Why ?
Imagine you are the engineer, standing next to your train depot and you yell at all your new shiny trains, Go Go Go Go! And all the trains just flood into the train network to do their thing.At the moment the immersion is broken by having to click on a train, move your mouse from the train to the switch button, click it, close the panel and do it all over again, I literally just want to watch all the trains leave the depot, because I like trains, and so do you.