Locomotive Speed Adjuster
Adjust the maximum speed of all Locomotives, either by a fixed percentage or set all to a fixed speed.
Slower locomotives are cheaper to buy, and have lower ticket prices enabling longer routes (especially useful for cargo).
Default settings scale locomotive speed to 50% of their normal value, you can adjust the configuration values in
Steamsteamappsworkshopcontent4468001471880075mod.lua
You can set locomotive speed to either a fixed percentage of their default values, or set all locomotives to a fixed maximum speed, or limit all locomotives to no more than a maximum speed (but not increase speed for slower locomotives).
Tractive Effort can also (optionally) be scaled inversely to speed adjustment: if enabled and the speed is adjusted to slower than default the locomotive will gain a proportionate amount of tractive effort, while faster-than-default speeds result in lower tractive effort.
See also Wagon Speed Adjuster for the equivalent mod for wagons.