EMD SD50

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EMD SD50

Power type	Diesel-electric
Builder	General Motors Electro-Motive Division (EMD)
Build date	1980 – January 1986
Total production	427
Gauge	4ft 8.5in
Prime mover	EMD 16-645-F3B
Power output	3,500 hp (2,600 kW)
Disposition	most still in service as of 2005

The EMD SD50 was a 3,500 hp (2,600 kW) diesel-electric locomotive built by General Motors' Electro-Motive Division. It was introduced in May 1981 as part of EMD's "50 Series", but prototype SD50S locomotives were built from 1980; production ceased in January 1986. The SD50 was in many respects a transitional model between EMD's Dash 2 series which was produced throughout the 1970s and the microprocessor-equipped SD60 and SD70 locomotives.

The SD50 was produced in response to increasingly tough competition from GE Transportation Systems, whose Dash 7 line was proving quite successful with railroads. While EMD's SD40-2 was a reliable and trusted product, GE's line included locomotives up to 3,600 hp (2,700 kW) with more modern technology, as well as very competitive finance and maintenance deals.

GM-EMD had previously produced 3,600 hp locomotives, the SD45 and later SD45-2, but these used huge, 20-cylinder engines with high fuel consumption, and demand for them dropped sharply after the 1970s fuel crises. The SD50 used the same V16 645 as the SD40-2, but uprated to 3,500 hp from 3,000. This proved to be a step too far; the 50 series models were plagued by engine problems which harmed both sales and the reputation of EMD.

The subsequent SD60 model replaced the overstressed 645 engine with a new engine series, the 710.

The SD50's long hood saw changes from previous EMD models. The overall frame length was increased, and the long hood was made substantially longer. The resistors for the dynamic brake grid were moved from their previous location above the prime mover to a new, cooler location in front of the engine compartment air intakes, where they were more effectively separated from the rest of the locomotives' systems.

Contents 1 SD50S 2 SD50F 3 Original owners 4 Current owners 5 References

[edit] SD50S

The SD50S ("short frame") were prototype units built in December 1980. They were shorter than production locomotives by approximately 2 feet. All of these prototypes were sold to the Norfolk & Western and passed to the Norfolk Southern; they were withdrawn in the early 2000s as non-standard.

The designation also applies to five locomotives built by EMD Australian licensee Clyde Engineering for Hamersley Iron. These were also shorter than production SD50s, and were equipped with a special double cab roof for insulation against the hot Australian desert sun. When withdrawn from Hamersley Iron service, they were sold to National Railway Equipment Company and exported to the U.S. in February 1999 and used in national lease service. They were subsequently sold to the Utah Railway in June 2001, where they remain.

[edit] SD50F

The SD50F was a Canadian cowl unit version equipped with a "Draper taper" (inset section aft of cab for limited rear visibility). 60 were built for the Canadian National Railway as road numbers 5400-5459.

[edit] Original owners

Railroad	Quantity	Road numbers
Baltimore and Ohio Railroad	20	8576-8595
Chicago and North Western Railway	35	7000-7034
Chesapeake and Ohio Railroad	43	8553-8575, 8624-8643
Conrail	135	6700-6834
Denver and Rio Grande Western Railroad	17	5501-5517
Kansas City Southern Railroad	10	704-713
Missouri Pacific Railroad	60	5000-5059
Southern Railway	20	6506-6525
Norfolk and Western Railway	6	6500-6505
Seaboard System Railroad	81	8500-8552, 8596-8623

[edit] Current owners

As of 2005, current owners and operators include:

• CSX: inherited SD50s from the Baltimore & Ohio, Chesapeake & Ohio, Conrail (split with Norfolk Southern), and Seaboard System.
• Kansas City Southern Railroad: retains the SD50s it originally bought.
• National Railway Equipment Company (NREX): lease operator owning ex CSX ex Conrail locomotives.
• Norfolk Southern Railway: Its own purchases, and some of Conrail's.
• Reading, Blue Mountain and Northern Railroad: 6 units purchased from the Union Pacific Railroad.
• Union Pacific Railroad: inherited SD50s from the Missouri Pacific (60, bought immediately pre-merger and delivered in UP colors), the Chicago & North Western (35 units) and the Denver & Rio Grande Western via the Southern Pacific (17 units).

[edit] References

• Lytle, Stan. EMD SD50 list. Retrieved on February 16, 2005.
• TrainWeb.com. The Unofficial EMD homepage. Retrieved on January 7, 2005. Contains fairly complete builders' records for EMD production.
• Union Pacific Railroad Locomotive Department (1994). Locomotive Diagram Book. Union Pacific Railroad Company. 

Diesel cab and cowl locomotives built by GM-EMD
Cab units (F- & E-units):	FT, F2, F3, F7, FP7, F9, FP9, FL9, TA, EA/EB, E1, E2, E3, E4, E5, E6, E7, E8, E9, AB6
Cowl units:	F45, FP45, F40C, F40PH, F40PH-2, F40PH-2C, F40PH-2M, SDP40F, SD40-2F, SD50F, F59PH, F59PHI, SD60F, F69PHAC
See also:	List of GM-EMD locomotives