It's my understanding that there was no vector in existence of this pony yet.
This is Steamer, the driver of the Friendship Express that frequents Canterlot, the Crystal Empire, and other destinations across Equestria, and named by the r/listofponies subreddit. His name is also based on a G1 pony that had a train cutie mark.
That said, of any of his few appearances on the show, none show a full body shot of him, though one that is nearly that kind of shot which shows his cutie mark had him sitting while driving the train in "MMMystery On the Friendship Express" (Season 2, Episode 24). If I had found another shot of a stallion sitting in a similar manner, I would have vectored that pose first (I don't have an idea of what his hindlegs would look like in that position).
Only a fraction of his tail was ever shown on the show at the time I first vectored this, and I did not see any other pony in the show that had a tail still even remotely similar to his (fortunately, his seemingly unique mane was shown much more often). So initially I recycled his tail from All Aboard, the other train pony, until Episode 5 of Season 4 aired, where the full tail model was shown.
What I have vectored here is actually originally a pose of Meadow Song's from "Games Ponies Play" (Season 3, Episode 12), modified and transformed into Steamer, for universally-usable…ness.
The most interesting thing to make while doing this vector? Whatever he's wearing around his neck, both setting and layering it relative to the rest of him. I'm not sure what it is, actually.
Time: 7 hours