1. Full Save and Load that Choo Choo will conuting train line that saved than forgot the work in Progress
Probably not for a while. You'd have to save a LOT of state to remember "where you left off". However, it may be possible to either store, or detect, open ended crossings and resume expansion from those... Hmm, I'll keep it in mind!
Switching new englines First Steam Train to Asiastar than Autorenewing the trains.
Probably not, I tend to put off those boring "management" tasks and focus on the network building. It could perform much, much better if I did some more train management... but I just don't care enough
The goal for ChooChoo isn't to be the most efficient competitor, but to build stuff that looks interesting, after all. But more efficiency does let you build more stuff...
Remove unused Cargo lines and any parts of unused tracks and station and even remove full network if no trains running them, Infrastructure maintenance and Inflation + no train running = network money losing!
I'll go with "maybe". Station maintenance is really cheap and unused rail is free, so it's easier to just let it rust... but I admit that there's an aesthetic reason for cleaning up unused stuff, so I might, at some point.
After the bug fixes, I've got some plans to let it try harder to find sites to build stations, so it can grow even bigger networks. Then, I want to look at running freight trains, as well.