I noticed that the maintenance on rail masonry bridges is, rightly, less than wooden bridges. However, for road bridges, the reverse is true, which I think is incorrect.
I believe the intention is that whilst masonry bridges are more expensive to build, the ongoing costs are much lower.
Brick rail bridges have a higher maintenance cost also, but I believe this is meant to reflect them having a higher speed limit / the track component being better, rather than the structure.
I will have to look into this in more detail when I deal with the balancing of costs, hopefully in the new year after some balance critical features are implemented.