Yes they did, and no they were not.
The two 2-6-6-2t articulated engines were purpose built for the Uintah RR by Baldwin. They were the ONLY narrow gauge Articulated engines in the USA. Baldwin built several for lines outside of the US, Mexico, Central America, and South America being the biggest users.
These engines were capable of traversing the 7 1/2 percent grades and 60 degree curves with ease. They served the line for several years but when the line folded, they were sold off to the Sumpter Valley RR. There they had the watertanks removed and were converted to tender engines. The Sumpter Valley didnt last long after receiving the two engines. They were then sold off to a line in Central America where they spent there last days.
While on the Sumpter Valley and in Central America it became apparent that converting them to tender engines had been a very bad idea as the traits that made them such wonderful performers on the Uintah RR , tenatious grip on steep grades and strong traction pulling power, had been lost once the watertanks were removed. Indeed in Central America they had reputation for being “slippery” and had a hard time pulling a moderate train over a 3 1/2 % grade.
They lasted in storage until the early 60’s several train buffs were trying to raise fund to purchase one of them and return it to the US but the deal fell thru and they were scrapped. That is a great shame, imaging riding behind one of these restored to a tank type original condition on a line like the Durango & Silverton or the Cumbres & Toltec.