I suggest when you define an image created by several layers and then group them, be possible to copy this image to another locomotive, wagon or freight car. For example could be like a logo, or lettering on the "rail vehicle",- that takes lot of time and work to do it-, that "layer group" could be copied to another one. I mean, not creating a copy of the "rail vehicle, that already exists. To be able to copy to another different one too.. This will be very useful, and will allow to create, new liveries more quickly, and avoid to make all the work again for the same image, which usually takes much time, mainly if it is a complex one. It will be like a "copy and paste" when the data saved on the device memory. Hope this can be done for PC but also for PS4 and XBOX!
I haven't used it in a while. but iirc, the Forza livery editor has this or a similar feature, where you can take layer groups and appliy them to any car you want, without creating it from scratch each time.