This is a topic for me to mumble how great the Extended Gameplay Two mod is. If you don't know. EG2 is for Transport Fever 2 what Extended Gameplay and Immersion was for Transport Fever was. That thing you can see here: Extended Gameplay and Immersion ( EGI )
In a nutshell - EG2 is a script mod that is mostly about providing more 'game' to the game. Which means there are more decisions to make, and those decisions come with consequences, so for most occasions, when it comes to it, it becomes a game of tradeoffs. Especially on higher difficulty settings.
Which is the first thing this mod introduces - four distinct difficulty settings, from 'easy' which allows to pretty much play the game as a model railroad, to 'fever' which will test just about any player.
The focal point of this mod are railroads, so in order to make constructing them more involved 18 track types are introduced, all with varying maximum speeds and maintenance costs. Especially the latter part makes the game more strategic, as it encourages re-use of infrastructure to avoid runaway infrastructure cost.
Also - when it comes to track, the track laying tools limit the maximum curvature of track to the track's maximum speed. So 120km/h track will force 120km/h limit. This, coupled to 4-click gradient control when building allows for precise control of how track is laid - you can even easily transitional curves by using nothing more the game's in-built tools.
When it comes to rolling stock - the other fun feature of EG2 is randomization. Each wagon and locomotive is first analyzed towards realistic performance bracket ( based on year of introduction, capacity volume, power etc ) which then gets modified with a few random suffixes/affixes, thus creating an unique vehicle. Also - randomized unique vehicle. When generating a new game you select a 'seed'. Each seed corresponds to a different set of vehicles to choose from. Considering that each model gets about 15 versions, there are _literally_ thousands vehicles to choose from - albeit no more then five from a given model at a time. Also - the last five never expire, so you can easily use steamers in 2050, provided the gameplay justifies it.
There are also several aesthetic changes - such as fixed valve gear animations, fixed lods or other changes. For a detailed description please visit the mod's readme. Attached below.