(from Concrete on the wiki.)Concrete increases walking speed by 40% and decreases vehicle rolling resistance, allowing for extra acceleration and top speed, although each vehicle is affected differently;
On the wiki page for Locomotive it mentions that the train max speed does include train friction force as part of the calculation but it does not have any reference (other than having the word friction) to the concept of rolling resistance.
The question I have is does concrete and refined concrete have a measurable impact on train acceleration and/or max speed? How much of a difference is there between Concrete and refined concrete is there? (if any)
Of course this will turn into, should I place concrete (or refined concrete) tiles under my train tracks? Do I only need to put it under the stations or in places that I expect the most acceleration to happen?
Though now that I think of it, should also wonder if braking force/deceleration is affected as well. While technically I would expect the real force to be friction between the steel train wheels and the steel rails, having a consistent and sturdy surface in the form of a concrete base can help.