View source for GE U50

{{Short description|American diesel-electric locomotive class (1963–1977)}}
{{more footnotes|date=October 2011}}
{{Infobox locomotive
| name = GE U50
| powertype = [[Diesel-electric]]
| image = UP U50 50.jpg
| imagesize = 300
| caption = U50 #50 on an eastbound freight at [[Laramie, Wyoming]].
| designer = 
| builder = [[GE Transportation|General Electric]]
| serialnumber = 
| buildmodel = U50
| builddate = 1963 - 1965
| totalproduction = 26
| aarwheels = B+B-B+B
| gauge = {{RailGauge|ussg}}
| trucks = 4
| bogies = 
| wheeldiameter = 
| wheelbase = 
| length = {{convert|83|ft|6.5|in|m|2|abbr=on}}
| width = 
| height = 
| axleload = 
| weightondrivers = 
| locoweight = <!-- {{convert|xx|ST|LT t|abbr=on}} -->
| fueltype = [[Diesel fuel|Diesel]]
| fuelcap = 
| primemover = Dual [[GE Transportation Systems|GE]] [[GE FDL|FDL-16]]
| enginetype = [[Diesel engine|Diesel]]
| aspiration = [[Turbocharger]]
| displacement = 
| alternator = 
| generator = 
| tractionmotors = 8
| cylindercount = 2x V16 Engine
| transmission = [[Diesel-electric transmission|Diesel electric]]
| maxspeed = {{convert|70|mph|km/h|abbr=on}}
| poweroutput = {{convert|5000|hp|kW|abbr=on}}
| tractiveeffort = Starting: {{convert|160000|lbf|kN|abbr=on}} <br> Continuous: {{convert|139500|lbf|kN|abbr=on}}
| locobrakes = [[Railway air brake|Air Independent Brake]], [[Dynamic braking|Dynamic brakes]]
| trainbrakes = [[Westinghouse air brake]]
| safety = 
| operator = [[Union Pacific Railroad]]<br/>[[Southern Pacific Railroad]]
| nicknames = U-Boats (UP)<br/>Baby Hueys (SP)
| locale = [[North America]]
| deliverydate = 1963 - 1965
| retiredate = 1973 - 1977
| scrapdate = 
| currentowner = 
| disposition = All scrapped
}}
The '''GE U50''' was an eight-axle, {{convert|5000|hp|kW|abbr=on}} [[diesel-electric locomotive]] built by [[GE Transportation Systems|GE Transportation]]. They were twin-engined locomotives, combining two {{convert|2,500|hp|kW|abbr=on}} [[diesel engine]]s on one frame.

==Configuration and History==

The U50 rode on four two-axle [[bogie|trucks]], grouped in pairs linked by [[span bolster]]s, giving a [[wheel arrangement]] of [[AAR wheel arrangement#B.2BB-B.2BB|B+B-B+B]]. The trucks and bolsters were re-used from scrapped UP [[Union Pacific GTELs|turbine locomotives]] built by GE during the 1950s. Owing to the wheel arrangement, the U50 was sometimes inaccurately referred to as the '''U50D''', a back-formation from the [[GE U50C|U50C]] name given to the six-axle units. The name is incorrect and was never used by the manufacturer or the railroad. None of the U50s rode on D trucks in any case. It is also sometimes referred to as the '''U50B''',<ref>{{cite book| title=The Great Book of Trains| first=Brian| last=Hollingsworth| publisher=Salamander Books Ltd. (UK)| year=2003| page=323}}</ref> but this is incorrect as well.

The U50 was built in response to the [[Union Pacific Railroad]]'s requirement, issued in the early 1960s, for a {{convert|15,000|hp|kW|abbr=on|sigfig=3}} 3-unit locomotive intended to replace the turbines. The design was effectively two [[GE U25B|U25B]] locomotives on a single frame; each [[diesel engine]] and generator powered only the two trucks at the same end. Three were delivered to the UP in October 1963, and three to the [[Southern Pacific Railroad]] in May and June 1964. Other locomotives built to this requirement were the [[EMD DD35A]] and the [[ALCO Century 855]].

The Southern Pacific kept the three but did not order any more. They were kept on the roster until the late 1970s but were often sidelined. While the UP's units were nicknamed "U-Boats", the SP's units gained the nickname "Baby Hueys" from the [[Baby Huey|cartoon character of the same name]].<ref>{{cite web| url=http://espee.railfan.net/spu50.html| website=My Espee Modelers Archive| title=Southern Pacific U50| last=Percy| first=Richard A.| access-date=January 14, 2005}}</ref>  Original numbers were #8500 - #8502; they were later renumbered #9550 - #9552 and renumbered again to #9950 - #9952. Southern Pacific's three units differed from the Union Pacific U50s by having a front cab door and headlights in the hood beneath the front windows.

The Union Pacific was more satisfied with their three and ordered 20 more. A batch of 12 were delivered between July and September 1964, while a final eight were built May through August 1965. They were numbered #31 - #53. UP #52 was delivered with a Cummins PT fuel system and rated at 5,600 horsepower. The #52 had a standard fuel system installed in October 1966 and was rerated to 5,000 horsepower.

Twenty of the Union Pacific U50s were withdrawn from service in 1973 and 1974 and traded in to GE for [[GE U30C|U30Cs]]. The last three Union Pacific units remained on the roster until April 1977. The Southern Pacific's three survived in service until 1977; all were sold for scrap by 1979. No examples of the U50 type were preserved. 

==See also==
* [[GE U50C]]
* [[Union Pacific GTELs]]
* [[EMD DD35A]]
* [[ALCO Century 855]]

== References ==
{{Reflist}}
* {{cite web| last=Komanesky| first=John| others=et al| archive-url=https://web.archive.org/web/20050302161701/http://www.thedieselshop.us/GE_U50.HTML| archive-date=2005-03-02| url=http://www.thedieselshop.us/GE_U50.HTML| title=General Electric U50 Roster| access-date=January 14, 2005}}
* {{cite web| last=Strack| first=Don| url=http://utahrails.net/up/diesels/up-diesel-story-1934-1982-d.php| title=A History of Union Pacific Dieselization, 1934-1982, Part 4| website=Utah Rails| access-date=January 14, 2005}}
* {{cite web| last=Strack| first=Don| url=http://www.utahrails.net/up-diesel-roster/classic-index.php| title=UP Diesel Roster, Classic Index Page| website=Utah Rails| access-date=January 14, 2005}}
* {{cite web| last=Strack| first=Don| url=http://www.utahrails.net/articles/up-dash8.php| title=Union Pacific GE Dash 8 Locomotives| website=Utah Rails| access-date=January 14, 2005}} Mentions earlier UP GE purchases also.
* {{cite book | author=Union Pacific Railroad Locomotive Department| title=Locomotive Diagram Book| publisher=Union Pacific Railroad Company| year=1979}}
* {{cite magazine| last=Withers| first=Paul K.| title=Union Pacific U50s| magazine=Diesel Era| volume=20| issue=4| date=July–August 2009| pages=21–38}}

{{UP Giants}}
{{GE diesels}}

[[Category:Diesel–electric locomotives of the United States]]
[[Category:General Electric locomotives|U50]]
[[Category:Union Pacific Railroad locomotives]]
[[Category:B+B-B+B locomotives]]
[[Category:Railway locomotives introduced in 1963]]
[[Category:Scrapped locomotives]]
[[Category:Freight locomotives]]
[[Category:Standard-gauge locomotives of the United States]]