This is a "potentially great game"; however, it does have some fairly significant flaws. The most notable (for me) are as follows:

1. Maps
2. Time Frame Change

MAPS:
I believe the game would benefit greatly by having one (1) map per region. In other words, an accurately depicted map of the USA (lower 48 States) Europe and Asia covering the entire region/country rather than the option of very small - very large.

Having one map per region, with all major Cities depicted, means only one map loads each time and does not need to be "regenerated" with each game - it remains the same for each region/country. That means a person can choose which cities they play in and with instead of having cities randomly placed on a map as it is now. While I am no a fan of SCS and the ETS games, creating the "maps" as they have done for those games would enhance the Transport Fever series greatly.

TIME FRAME CHANGE:
The rate of change in time is (frankly) ridiculous and way way too quick. It needs to be slowed down greatly. When it takes a train 5 days (according to the rate of time change in the game) to clear a station once it begins moving, then something is definitely wrong.

I have a game up with a train connecting Nashville to Antioch, an actual distance of only 12 mile (on average) yet it takes a train (travelling at 60 MPH) "72 days" to make that journey??? In reality, it should only take around 20 - 25 minutes (MAXIMUM). Simply put, the time to distance ratio is way way off.

Reducing the "Rate of Change for the Time" would open up a few additional features as well. Firstly, it would/might permit a Day/Night inclusion which I think would be great. It would/might also permit the inclusion of "Climate Change" and "Environmental Conditions" such as changes in weather including Sun, Rain, Snow adding to the realism of the game.

In short, the Rate of Change in Game Time needs to be drastically slowed down to the point of 1 Day (Game Time) being the equivalent of (perhaps) 2 or 3 Minutes (Real Time).

As first mentioned, while this is a "good game" as is, it has the "potential" to be a really "great more realistic game".

I (obviously) don't know how Urban Games created the game; however, I do know that ETS2's map of Europe covers about 90% of Europe, at the moment, therefore it is possible to create a map of an entire country that a computer can and will run.

As for the time scaling if it is designed solely for the purpose of maintenance then it really does need to be slowed down as I suggested. If what you say is correct, your paying out maintenance money at a MUCH GREATER rate than you are making it. That, in itself, makes the game unrealistic.

Nah you didnt got me right on this. You can do big maps like US/EU (see campaign or you can find some on skymods or transportfever.net) but they wont fit the 1:1 scale. So Paris - Rome would be under 20km distance. And yes other engines can handle that, but they dont have to handle all the terrain AND some thousand sims searching for their transportation way.

I guess you could mod that (time progression can be modified up 4x i believe - you can also somehow make a "time stop"). I also found it weird sometimes, but its a game you also want to have progression. Time scale is mostly same for most transportation games but much different from a driving simulator. But if you are more interested in a 1:1 scale model railway without economy - you can hit that mode.
But think on your suggestion. With a sim-day as a real 3 mins. So one Sim-year would be real 1095mins. (still a 300mins = 5 hrs under time compression). How many days you wanna play until a new train gets available ?

Yes maintanance is a unreal money sink, but its same for income. You earn easy millions, you sink most of that in the beginning for maintanance, but then youll earn fast enough to invest big in new tracks/trains. it has its balance - but its not a good balance. But alot of smaller balance mods are already out, and some modders fiddling on mods to do a better balance. Still an overall game balance (including mods) is much bigger workload then just to Blender and script a full new train set.