The UP's three cylinder 4-12-2's were built in five orders, classed UP-1-UP-5, for a total of 88 engines. Class UP-1 and UP-2 were built with dome throttles, hence no outside linkage. Classes UP-3, UP-4, and UP-5 were built with American Multiple front-end throttles. The UP-5 class were also built with one piece cast bed frames as well. Alco built the #9000 with blind drivers on the third and fourth axles. UP replaced the tires with flanged ones upon delivery. There were some numbered in the 9300 series for use on the OWN line, but they had severe problems on the curves, and so were reassigned to UP proper and renumbered into a slot in the 9000 series. OSL also had some assigned as well in the 9500 series.
I have the HO scale MTH model with working Gresley valve gear and center cranked axle and rod. Mine is numbered 9503 for the OSL. I added a Cal Scale front end throttle detail set to it to make it more correct. However, like it's O gauge sister, it has the weird square sand box. I've given some thought about how to correct it, but for now I'm just leaving it as it is.
Stuart
