Tyler, that appears to be a homemade creature, There was a chain drive locomotive that was commercially produced , but they were not many of them. I'm not familiar with them but my old cohort Rick Perry , down in Hurtsbourough Alabama is building a 3 foot gauge reproduction of one using a boiler and steam engine salvaged from a steam shovel.
The advantage of the Shay, maintenance wise was the bevel gears and universals were on the outside of the locomotive, so they could be lubricated without getting under the locomotive. They were the most produced, so parts and used locomotives were easy to find.
The biggest disadvantage of the shay was with track maintenance. the cylinders were on one side of the locomotivem mounted vertically, so the pounding of the clyinders was directly over one rail. In operations where the locomotive was not turned, this would result in one rail taking a greater beating than the other. I have a photo of a piece of track like that over my desk.
The climax had the universals and bevel gears down the center of the locomotive, harder to get to for maintenance, probably easier on the track.
The Heisler with the V cylinders, had universals and bevel gears down the center. They had the bevel gears in a housing though, so they could run in oil, and you would only have to go under there to lube the universals and the slip joints. also using side rods to power the 2nd axle on each side, reduced the number of Bevel gears, which kept manufacturing cost down.
I think one of my dad's books covers this subject, I'll Have to look around.
I have heard that some crews on modern outfits have not been fond of some of the climaxes, as they sometimes hop. I have seen photos of Heslers with a distinctive hop as well.
Bill