Comment by KronisLV

> RRT2 is my all time favorite game, and has yet to find a spiritual successor in my heart.

Aside from OpenTTD, the only games that come to mind are more modern in both their looks and how they play, but they might be worth a shot regardless.

Transport Fever (1 and 2) - the first game can be found for cheap, the second game has quite possibly the best UI of any game in the genre, plus you get trains, trucks, boats and planes, large and pretty maps with towns that develop into proper cities over time.

Mashinky - a more grid based game with trains, trucks and planes, as well as an interesting token based economy system, where you unlock new types of resources as you move along within the game world and therefore have to build out your network gradually, ensuring that everything works okay as it scales up.

Train World - a pretty recent game about trains, which has a larger scale than any of the other games I've played in the genre, might need a bit more polish but is pretty promising! It is focused purely on trains though, so is a bit more of a focused experience when it comes to actually laying out the network and setting up lines.

Workers & Resources: Soviet Republic - a slightly different genre (city builder), but it puts you in charge of both the economy aspect, as well as city building (and utilities like electricity, heating, water and sewage, which can be toggled on/off), production chains of various resources to use or export, transportation for citizens and a bunch more stuff. There's a lot of different mechanisms, but it doesn't feel horribly complex if you have some time to sink into it and it's quite lovely.

Honestly I also liked OpenTTD, but couldn't really get past the UI long term, it has that classic feel sure, but just wasn't quite as pleasant to use as in some of the other games.