Basically steepness of all maintenance cost multipliers seems to be unjustified high.oberhümer wrote: Doesn't sound that unreasonable for a high-speed line halfway across a 2048x2048 map - but I don't really play much at the moment, so I might be wrong here.
Income of railway line is proportional to its maximal speed, or at least, to square of maximal speed.
Therefore, change of maintenance costs should not exceed change of income,
in other case, using high speed line become less profitable than low speed one.
Your change coefficient is 2.75x
Speed change 80 to 125 km/h is 1.56x, 125 to 180 is 1.44, 180 to 230 is 1.28...
Even if squared, it is still less then 2.75.
I suggest to put just 2x instead of 2.75x in maintenance costs.
Construction cost are OK.