About a decade ago John Whelan and Bob Sanders uploaded a set of wagons that had been turned into scenic track objects (ie. snap to track like signals, buffer stops etc.) I cloned and uploaded some reskins of my own of some of these wagons. Check out the most recent revised versions of these uploaded by John:
<kuid2:86627:100478:1> LMS 10 ton van scenery
<kuid2:86627:100294:3> GWR 4 plank fast fish wagon w tarp scenery
<kuid2:86627:100420:1> GWR TEVAN van 19033 scenery
<kuid2:86627:100500:2> PO Vauxhall 5 plank V2 open door wagon scenery
<kuid2:86627:200477:1> Dance hall brake van scenery
<kuid2:86627:100080:1> LMS van vented scenery
<kuid2:86627:100320:1> GWR MINK V22 30 foot van scenery
<kuid2:86627:200463:1> SR 5 Plank wagon w normal mapping scenery
Don't know if the same principles could be applied to a loco as well as a wagon, but worth checking out the configs to see how it was done?