So, a very small issue appears when using the front and rear number light switches for the SD40... When you use the front switch, it only turns on the right number boards, both front and back. When you use the Rear lights, only the left ones, front and back, light up. Having both on will have both number lights front and rear on. This occurs on at least the PS4 and PC version of TSW2.
I've made a fix for this for PC users only fr the time being. https://mods.trainsimcommunity.com/...907-clinchfield-railroad-sd40-numberboard-fix