Hi!

Recently I've been working on a tool to calculate optimal route distance for max profit. Although I'm not finished with it I think it's good enough to show you: https://citymania.org/tools/profit. Not perfectly accurate yet (still have to reproduce some openttd bugs;) but it is pretty close so overall picture should be reasonable.

So let me know what you think of it, mb you'll have some ideas how to improve it. I was thinking of adding some train constructor instead of pre-defined trains and calculation for 4-station 2-way route (currently used 2-station one that isn't rly possible for, say, coal).

Wow that's very cool. Impressive work.

2-way SH125 coal trains do 1.3 trips/year while 1-way SH125 coal trains do 2.1 trips/year. It kind of shows why 1-way starts are almost as good 2-ways.

If you wanna improve it I guess more degrees of freedom is the way to go. As you say custom made trains and maybe even routes would be cool.