Being from back-east and a traction fan, what is so special about these locomotives?Wesley

While I am not prepared to address the issue of "what is so special about these locomotives"-I can try to offer some background on their construction.By the late 70's, the SP's fleet of 50+ U25B's had fulfilled their service life and had been retired. In order to gain additional service life from the locomotives, SP 'remanufactured' one unit at their Sacramento Shop. That would be the 3100, which is preserved at ? I think they begun a second one which was not finished due to excessive costs, for GE locomotive material is expensive relative to EMD. The second approach to this problem was to send four core units to Morrison-Knudson in Boise, Idaho to be remanufactured into MK model TE70-4S locomotives. The original GE FDL engine was replaced by a Sulzer (Swiss design) 12ASV 25/30 V-12 engine rated at 2800 hp. As Sulzer was a company who made liberal use of licensed production, the diesel engines may have come from a licensee in Poland.All of the engine support equipment was new-but the original GE GT598 main generator and auxiliaries, the 752 motors and perhaps a good deal of the controls were retained. The entire radiator cab was replaced with a unitized Behr (German) hydrostatic drive cooling package, with the dynamic brake grids retaining their traditional GE location on the engine cooling air intakes. There were also some new crew amenities such as electric heat, improved toilet, AAR control stand and perhaps A/C. The original GE engine cab was reconstructed and/or replaced to suit the taller outline of the Sulzer engine, with the new profile being carried forward to the operators' cab. I don't recall why-but they did not last long in service.One might suspect that the need to deploy metric tools for only four locomotives must have been a logistics issue. One also has to wonder about the cost abnd ease of procuring parts from Europe. Believe that the UP (and perhaps ATSF) also had a dalliance with this engine. In NJ, there is an MK built GP-9 with a inline-6 version of the engine on the property of the Morristown and Erie.

Didn't these locomotives also have prime movers which ran at a constant speed, like an F40PH with HEP engaged? Or, am I thinking of another 1970s 1980s SP locomotive experiment?

I think the primary significance of these locomotives is in showing the Southern Pacific's continuing interest in applying European diesel locomotive technology. They are a continuation of experiments that in the 1960's saw the importation of several German built diesel hydraulic locomotives - one of which is preserved in a deteriorated and modified form at CSRM. I think it would make an execellent interpretive at CSRM, accompanying the aforementioned unit and an unrebuilt SP U-25 B - could one be loaned to complete the exhibit?Tom Cornillie

FWIW, I wish CSRM would do something with the remainder of the former ATSF diesel locomotive collection that was deeded over to them rather than acquire yet another piece of junk. Last I recall, most of these units are sitting outside, with time having taken an obvious toll.I think the "Popsicles" are just a minor footnote in the greater picture-testimony to some good salesmanship on the part of M-K's Railroad Division and/or the stupidity of the buyer for forgetting some lessons learned with the Krauss-Maffei diesel-hydraulics. BTW, the balance of SP's U25's long ago went to Japan and have since returned as new Hondas and Toyotas.DPK

Just a minor correction the second "remanufactured" unit (3101) was completed by the SP. They were designated as U-25BE's. The one surviving unit ended up at the Orange Empire Railroad Museum at Perris CA. Unfortunately I do not remember which one it was.

Just a minor correction. The SP completed the second remanufactured unit (3101) before putting an end to the project. The units ran for a few years in the early 1980's before being retired. The preserved unit wound up at the Orange Empire RR Musuem in Perris CA. Unfortunately without digging through my photo's I can't remember which unit it was.

Most of the Santa Fe collection at CSRM is now indoors in the former SP loco and tank shops. At least one loco has been deassecioned and sent elsewhere.

Ya got me-Zog. SP did two units.BTW, the reason costs got out of hand is that SP decided to UTEX major components ( diesel engine, main generator, etc.) with GE rather than set up an in-house process line as they had done for EMD components. DPK

Correction: According to my Diesel Spotters Guide Update (1979), SP/M-K did FOUR units, 7030-7033.I'm sorry to throw a wet blanket on this proposal, but in the grand scheme of rail preservation, this must rank somewhere around #850 in my list of projects to get behind, somewhere after rebuilding a McKeen rail car and a PRR steam dummy for the South Jersey coastal island trackage that disappeared in 1934..........