As Chris said, the previous info is out of date.

These are GE 54 tons - the only two of this design built. GE did announce a U4B and U6B model in early 1956, but the 54 tons as built don't match either spec but are the evolution from the 50/52 ton model (SPng #1) and the later end cab Cat powered Universals. They are still owned by the Ashby family who used them when they operated Georgetown Loop. They moved them to museum in Golden in late 2004 where they were used at times, but they have been leased several times since to the current operator and both were there in use in mid-June when I was there. Serial numbers are 32658 & 32657 (not 32675).

Porter 1203 was sold by USG where it had blown two engines to private owners(s) who moved it to Huckleberry where it was eventually donated/purchased by them. After blowing that engine, it was sold years later to Sumpter Valley. It was overhauled by SVRR using a salvaged engine for Colorado Historical Society who owns the Georgetown Loop. After blowing two more engines, it was repowered with an Alco 6-251 salvaged from one of the White Pass & Yukon 90 class. Then it was traded to the Durango & Silverton who does use it on occasion. Two biggest myths over the years - nothing has ever been found to support it as being built for Pakistan, and it was a 6 motor C-C unit though the Loop apparently ran it for at least a while on 4 motors due to a failure and no spares.