This is one of my favorite game, some points that are missing (if you can manage it better).
ECONOMY CHAPTER :
- too hard (in hard level) at the beginning, only one solution to survive with trains is to use oil or food economy (budget can not support any empty wagons), so quickly boring start. May be cost of wagons is too expensive ?
- cost of construction does not change so much, so heavy cost becomes marginal costs after you have a working network. Same thing about cost of maintenance : tracks looks to be "free", so making a lot of tracks or station is not a problem. A better balance in tracks/trains maintenance costs would push to optimize the number of tracks, making more realistic and beautiful solutions.
- economy does not looks to change (what is valuable at the beginning is the same than later, rules of paid prices should change, economy too (are you sure that the oil economy in 1850 is not a non sense ??? plastic did not exist in 1850... but for example some automotive industry growth can be interesting). What about garbage for example ?
- closed economy : if you can export some finished products or import from some gateways of the map, it can bring some new ideas. Same thing for passengers, stations in the borders are always less interesting than in the center of the map. May be you can reserve a track to external deliveries (IA controlled) ???
- no war, no crisis that affects production or transports. We just adjust capacity to industry growth that is depending for network... If you have a doubled price for steel because of war, lower or upper revenues from passengers or goods... it can help managing capacity to real situations, closing or re-opening lines...
TRANSPORT MANAGEMENT CHAPTER :
- Existed previously : what about multimodal stations, bus and trains should be only one stop, and may be a train station can have passenger and goods terminals. This creates unuseful complications in stations management, so i every time makes goods lines and passengers lines (also my remark on costs of constructions...), it can be more insteresting to use the same lines.
- Multi goods trains : close to be impossible to have goods trains filled in both sides, making them impossible to use in the beginning (except for oil and food). No solution, but the management of empty wagons is not wonderful...).
- steam to electric : except power and cost, there is no change. Managing water, coal with associated costs, same thing for electric lines : power stations, maintenance centers... would help to make real choices of traction type, and to use diesel, steam or electric in real strategic choices. Why not having reduced costs if you can bring coal (or fuel) to your own facilities ?
IN MY DREAMS : Cooperative or competition play with multiplayer... or IA.
I hope this can help and would enjoy TF2 anyway !!!