@isodoro In theory it should work. But depending on how much faster the new trains are, the length of overtaking track might be prohibitive. It could prove very difficult to get it working in practice, but I am going to experiment, to see if it works. I’d like to better understand the logic behind when a train checks for a clear path, and whether a train can be persuaded to move off the track chosen by the line because the alternative path is clear.
I agree – having some fast trains is pointless, because they always jam up behind the slower trains. It’s not too bad if the newer trains are only a little faster, but have better capacity, or running costs. But it’s the reason why I prefer to switch all of my trains to the same type as quickly as possible.
I also agree that the micromanagement of lines to add waypoints feels prohibitively awkward. I already spend far too much time tweaking routes and adjusting vehicle updates. But it is a way to guarantee which trains select which tracks. Whether the layout permits overtaking, remains a speed/distance calculation problem, though.
Personally, I suspect that the expense of changing all trains to the same type, is less trouble than building a working overtaking track. I use the automatic vehicle replacement tab on the Line window a lot. Select the appropriate vehicle, then switch it to replacing at 25% life. You get about half of the old train’s value refunded when it is sold, the trains update automatically at a station, maintaining the passenger counts and smooth running of the line, without needing the manual intervention of sending trains to depots and buying new trains to replace them. Usually the existing fleet is already old enough for an instant replacement when something appropriate to replace them turns up.
I do the same trick for trucks, buses and trams. But only when a really interesting / useful new vehicle is released. Like a bus with twice the speed and more passengers, for intercity haulage.