I added a useful feature to your mod called Efficiency. It is measured as cashflow / income (in percent). Absolute values change significantly during the game, so it's difficult to track whether your transportation network is effective. But if you look at efficiency as a percentage, it’s much easier to monitor the impact of your changes or optimizations to lines, tracks, road networks, etc.

Also, for example, if you’re playing on “easy” difficulty and see that your efficiency is over 20%, it might be a good time to try “medium.” You shouldn’t jump to “hard” unless you’re able to maintain efficiency above 40%.

Please accept my friend request on Steam so I can send you a link to the modified code via chat. If you like it, you may include it in a new version.