Feature idea: track maintenance costs

[Cirno the Ice Fairy]

There are currently maintenance and running costs for trains in the game, but, IRL, one of the most expensive part of a rail network is track maintenance.

The idea is that, as an option for people who wants, tracks will cost a certain amount of money per meter of track (per day or per week). Bridges, tunnels and high-speed tracks also cost a certain amount.

Why not, afterwards, make the cost of a section of track dependent on the speed limit (a section of wooden track at 160km/h will cost more than a section at 10 km/h)