EMD SW1

Infobox Locomotive
name=EMD SW1
powertype=Diesel-electric


caption=Southern Pacific Railroad SW1 #1000, photographed when brand new in 1939.
builder=Electro-Motive Corporation (EMC) later General Motors Electro-Motive Division (EMD)
builddate=December 1938 – November 1953
buildmodel=SW1
totalproduction=661
gauge=RailGauge|ussg|lk=on
primemover=EMD 567 or 567A
enginetype=Two-stroke diesel
aspiration=Roots-type supercharger
cylindercount=V6
poweroutput=convert|600|hp|abbr=on|lk=on

The EMD SW1 was a convert|600|hp|sing=on diesel-electric switcher locomotive built by General Motors Electro-Motive Division between December 1938 and November 1953. Final assembly was at EMD's plant at La Grange, Illinois. The SW1 was the second generation of lightweight switcher from EMD, succeeding the SW and SC. The most significant change from those earlier models was the use of an engine of EMD's own design, the EMD 567 engine, here in convert|600|hp|abbr=on V6 form. 661 locomotives of this design were built, even though diesel switcher production was suspended between 1942 and 1945 by the War Production Board.

Production changes

Like most long-running locomotive models, a number of changes were made to the SW1 over its production life. Internally, the post-1945 locomotives were somewhat improved, and used an updated 567A engine.

One easily spotted change is the shape of the two center cab windows over the hood, which were curved to follow the roofline originally, but became flat-topped after mid-1950. Another easily seen is the taper of the hood to the cab, which was a two-stage taper in earlier units but became a single taper in later production. Very early locomotives were delivered with a stubby exhaust stack, but this did not lift the diesel exhaust sufficiently clear of crew visibility. All later units were delivered with EMD's standard conical switcher stack, while early units were generally modified with taller stacks too. Early locomotives had a single large headlight, while later had twin sealed-beam headlights.

Identification

The SW1 appears very similar to its SW and SC predecessors, but has only a single stack instead of two, a significantly shorter hood and a larger rear platform, no small louvres on the front top hood sides, and a large grille instead of lifting vents on top of the hood front. The sandbox in front of the radiator is somewhat smaller on the SW1.

Compared to later EMD switchers, the SW1 has a much shorter hood, large platforms at each end, a single exhaust stack, and a large 'satchel' type sandbox.

Original owners

* There were 7 units built as EMD demonstrators: #152 (to Scullin Steel #6), 700 (to Manufacturers Junction Railway #7), 755 (to Inland Steel #51), 804 (to Southern Pacific Railroad #1000, pictured above), 905 (to Central of Georgia #1), 906 (to Western Pacific Railroad #501), 911 (to Great Lakes Steel #11)

Preservation

* The first SW1 built by EMC in 1939 is now preserved at the California State Railroad Museum in Sacramento, California. The locomotive worked for Holly Sugar in Santa Ana and Tracy as the company's number 1. The museum donation was a coordinated effort between the museum, the Pacific Coast Chapter of the Railway and Locomotive Historical Society and Spreckels Sugar (the locomotive's last owner).

* Sahara Coal SW1 #6 was purchased in the 1990s by the Crab Orchard & Egyptian Railroad in Marion, Illinois and is still in operation.

* EMC demonstrator 906, sold to the Western Pacific Railroad as their 501, is preserved at the Western Pacific Railroad Museum at Portola, CA. It has been restored back to its original WP image. This locomotive was the Western Pacific's first diesel-electric engine.

* Another former Western Pacific SW1 is also preserved at the California State Railroad Museum. Later sold to WP subsidiary Sacramento Northern, this engine is preserved as SN 402, painted in the famous silver and orange "Zephyr" colors that the WP roads used through the 1950s and 1960s.

* [http://zwsr.org/ The Zanesville & Western Scenic Railroad] Operates a preserved SW1 on its scenic line in Fultonham, Ohio.

* Metra commuter rail inherited two SW1s from the Rock Island. The two engines are used for Yard Service and power on work trains on the Metra Electric and Rock Island lines. Built in 1939, they are rumored to be two of the oldest operating diesels in Illinois.

*The Wilmington and Western Railroad owns and operates two SW1s in tourist passenger service. One is from the Baltimore and Ohio, and the other is from the Lehigh Valley.

*The Baltimore & Ohio Railroad Museum, Baltimore, MD has former SW1 Pere Marquette Railway #11 in operating condition at last report.

References

*
* (July 2005), "Preservation Briefs", "Trains Magazine", p. 71.
* TrainWeb.com. " [http://www.trainweb.org/emdloco/index.html The Unofficial EMD homepage] ". Retrieved on January 7, 2005. Contains fairly complete builders' records for early EMD production.
* Electro-Motive Division. (1949). " [http://gelwood.railfan.net/manual/sw1-gen.html EMD Operating Manual: 600 & convert|1000|hp|abbr=on Switching Locomotives] ". General Motors Electro-Motive Division, La Grange, Illinois.