No clue, but you can be sure it’s a black smoke generator 
I see quite a few of those on the road hauling anything from travel trailers to cargo trailers. Probably gets from 10 to 15 MPG, depending on the load. I’ve seen some pretty nice rigs…
My work truck is a 4WD Kodiac. Gets around 10mpg here in the mountains. The smaller Ford Super Duty we were using was getting 6mpg.
Ralph
This afternoon the Gateway Garden Railroad Club’s Geoff Goerge, and contributor here, was interviewed on KMOX radio about his light and train display. He talked for about 5 minutes on the afternoon radio talk show out of St. Louis, Missouri. He emphasized that his light display is used as a fund raiser for “The Back Stoppers” a local organization that helps the families of fallen policemen and fire fighters, plus collecting cans goods for a local food bank. His light display runs through the 27th of December from 6 pm to 10 pm Sunday through Thursday and 6 pm to Midnight on Friday and Saturday evenings.
You can see examples of his light display at his website