I know that other railways (suck as the PRR, SF, & the E&L) had some unique locomotives, including the 4-4-4-4, the makeen motor car, & the
2-6-6-6-2, but very few companys have owned as many oddities as the
UP (or have survied the merger period like the UP).
Least successful diesel on UP would be a tossup between the C855 and U50C. Dishonorable mention would go to the Baldwin Centipede, since the order for two was cancelled before they were completed at Eddystone.
UPs most successful diesel was the SD40-2.They had close to 1000 of these engines,and may have gone over 1000 after all the mergers,if the SP SD40T-2s are counted.These engines can still be seen on many UP freights and some of these are over 30 years old.
I’d agree on the SD40-2 and for steam, I’d think the heavy Mikados. Not very spectacular, but very cheap on input and they ran day after day after day for a long, long time. Least successful steam would have to be the 4-12-2, and least successful diesel, the C855. At least the U50Cs ran sometimes.
OS
I’m not sure I’d agree; the 4-12-2s were built in quantity and did a useful job. They enabled the UP to increase the speed of its freight trains substantially over the compound Mallets they used for the heaviest trains before. They were far from without problems, however, but I’m not sure they’d count as ‘least successful’.
Least successful steam probably were the GE steam turbine pair.
I’d say the Challengers were the most successfull steam locos on the UP. They ran on almost every division, puled passenger, fast freight, and even drags, and didn’t have a lot of maintenance problems that I’m aware of. Least successfull would be the original 3 cylinder 4-10-2’s, although they did end up performing well in helper service on Cajon after they were converted to 2 cylinder locos. Among strictly experimental, the steam turbine and coal turbine were probably the least successful, but IMO you really can’t blame the large RR’s for experimenting.
IMO
The steam and coal turbines were the worst. The challengers the best, closey followed by the 4-8-4 northerns.
Diesel…
Best…the SD-40 and today the SD-70
Worst…well they had alot of hanger queens but my picks are the:
DD40AX and the GP 40X. Not that they were “bad” but…they truly were beasts for one master.
The SD50?
I think it was a good engine, just got eclipsed to fast by technology and the newer models coming out.
You had the -60’s then the staple… the SD70. Which my guess is probably the best balanced desiel engien ever built. Hence the popularity of the Dash-9(AC4400) which is pretty close to the SD70 (hope I am right on that). Only reason why then the 80’ and 90 Series of SD never took off. Guess they were just too big[:0].
Defination of least succesful, “Most purchased (units) balaned by how long they were in service”.
My guess would have been the DD44 Seems like they had quite few of them but they didnt last very long. Someone at UP fell for the sales pitch.
John k