General economy balance

[AlphaCentauriBear]

Hello, fellow players.
I adored TTD and OpenTTD makes it easier to play. Nice game.

I am thinking about how to make it slightly more challenging for player. It starts interesting but quickly gets boring after cash flow is established. Money just keep growing permitting player to do all kind of stupid things. I would envision game keeps challenging player even with invention of more and more advanced transportation.

True that player can set a goal for themselves but with that it no longer an TTD game but the game invented by the player. Equally, one can take any game and turn in in some sort of meta game adding more rules. I would prefer keeping winning restrictions within game itself. This way, player can utilize all of their transportation building mastery to actually beat it and not get bankrupt. If you share my attitude, read on.

Expectation
Player is engaged throughout the game to improve company economical standing. Not doing anything leads to slow degradation. Doing stupid things leads to degradation faster.

Analysis
Once trade route is established it generates income indefinitely. Expenses are irrelevant as long as income is positive. Increasing number of routes increases income to the level when player cannot spend it faster than receiving. Beyond that point nothing matters. Even though inflation of costs is faster than one of transportation prices it takes like 200 years just to reach the point when it become significant.
Increasing expenditures (running costs, maintenance) does not help as they will be either lower than revenue allowing income to grow infinitely or higher than revenue preventing making money at all from the beginning.

Proposed solution
Increase difference growth between transportation prices and costs so that old transportation means become ineffective sooner and would require more faster more modern vehicles and more straight transportation network.
Terraforming is very expensive so that player has to choose whether invest a lot into more straight path. Optionally, invest later into more straightened path.
Road/rail maintenance is very high to discourage extra road placing just in case. Player should try to build more optimal network.
Industry is less forgiving for long interval service. Frequent service should be more important than distance traveling.
Transportation prices drop significantly with delay. Discouraging transporting to long distance without adequately fast vehicle/network.

Some generic balance between revenue and expenses on top of this
Tested different settings (configuration and basecost parameters). Results are acceptable (not too restrictive and not too permissive) with following parameters:
running cost: high
maintenance: high
raise/lower land: 4x
train engine running cost: 4x
aircraft running cost: 2x
rail maintenance: 8x
airport maintenance: 1/16

[dol422]

There are basecost mods available which you can increase costs by I believe up to 16x. Combine that with infrastructure maintenance which heavily penalises large networks and it would become too cumbersome eventually, unless obviously you have billions to spend.

[AlphaCentauriBear]

Working out my NewGRF now that is somewhat based on Simple Cargo Profit. Just fixed it here and there.
Essentially, transferred cargo payment does not depend on distance anymore and is paid as if cargo was transferred by 20 tiles. That makes player (me) to fight for shorter transfer route instead of for longer route as in vanilla. That makes a perfect sense and challenge base. I like it a lot! I have not only fight for shorter transfer routes but to understand my network in its entirety and industry development. Sometimes I may choose to deliver cargo to already established industry to increase its output that I am transferring too. Searching for industries closer to major cities to deliver processed goods quicker.
The running cost and infrastructure becomes a very important factors. I may choose very cheap engine with low running cost on short routes but have to use more powerful ones on longer routes to maintain good station cargo rate. I also have to cut on station sizes to have them exactly what I need. Same for rail lines. Cannot just leave them there in large quantities. Need also revisit existing routes to adjust them to better values. Unlimited fun.

Other configuration tweaks

Game settings

Inflation is ON
That one is very important as it also introduces slower cargo delivery payment growth than the cost of everything else. That makes game slowly harder and harder forcing player to use faster engines, more optimized network, hunt for large industries and, most importantly, manually develop industries and towns to extract better revenue from them!

Interest rate = 4%
Higher interest rate puts additional pressure on borrowing money. With 2% it is almost no impact.

Subsidy multiplier = 3x
Subsidy duration = 4y
Very important to hunt for subsidies in this tough game. That should become an important aspect of the game with such tight difference between revenue and expenses. That is why they are so lucrative. I think one year was too short to support it. Four years is more like it. After that player can even disband the route accumulating enough profit to go to next subsidy and on and on. The important part is that with these settings they may be important throughout the game and not only early on.

Infrastructure maintenance is ON
Mandatory. Penalizes longer transportation routes, excessive stations, etc. Discipline player to build only what is needed and revisit it periodically.

Running cost = low (no changes)
This is set in basecosts GRF instead.

Construction cost = low (no changes)
I found this less important comparing to maintenance. Can be adjusted in basecosts GRF.

Plane speed factor = 1/2
With distance not contributing to carto transportation payment this setting gives planes slightly wider operational range allowing them to not suffer too much penalty from delivery time factor decay.

Disasters is ON
Recessions is ON
Completely optional. I am trying it out to see if it gives me more stuff to manage. If it becomes too micro - I'll turn it off.

Town allows airports by noise is ON
Also optional. I feel like it adds certain limitation on what size of the airport and how close to the town one can build.

BaseCosts

raise/lower land = 4x
Specifically to restrict player from flattening out everything without thinking.

train running cost = 2x
Slight increase to compensate for train ability to pull unlimited cargo capacity with the singe engine. Other transport type engines have fixed capacity. This even could be too not enough. I need to play and see whether 4x is better.

airport maintenance = 1/32
Not related to this mod. Just somehow airport maintenance is absolutely ridiculously high in vanilla settings.
Basic maintenance cost of the 5 tiles railroad station is 100 GBP and small 3x4 airport is 40 THOUSANDs GBP !!!
Even with supposedly higher passenger traffic it is impossible to earn that much.

[AlphaCentauriBear]

The ideal transport route!