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EMD GP7 - Atlantic Coast Line (ACL) No. 1804

ACL 1804

Left, No. 1804 at the museum in December 2010.
Photo courtesy

Interesting facts

The GP7 was the first in General Motors Electro Motive Division's "GP" series. GP stood for "General Purpose," and the number "7" was used because EMD's E7 and F7 cab units, as well as its SW7 switcher, were all in production at the same time.

During its early development, the GP7 was described by EMD's then Chief Engineer, Dick Dilworth, as being so ugly that no railroad would want it seen on their mainline or anywhere near their head office.

The model is often referred to as a "Geep" but, as the name took hold, EMD General Manager, Nelson Dezendorf, issued a memo to staff pointing out that a jeep was actually a four wheel military vehicle, and forbade the use of the term in the company's offices.

Below, No. 1804 in the museum yard in April 2009. Photo by Eric Kreszl.

ACL 1804


After WWII, a growing number of U.S. railroads began the shift from steam to diesel motive
power, and the reasons were overwhelmingly

Steam locomotives needed large pools of labor
to maintain and run them, as well as sizeable servicing, coaling, and watering facilities. Diesel locomotives, by contrast, required far less time
and labor to operate and maintain. They also had much higher thermal efficiency, more than 40% compared to about 6% for a single expansion steam locomotive, had higher power-to-weight ratios, and caused less damage to tracks because they had no unevenly balanced reciprocating parts like a steam locomotive's connecting rods (an effect called "hammering" that increases with speed).

Although EMD's F and E units had proven popular, the company's first foray into the road-switcher market was much less successful: its BL2 sold only 58 units in the 14 months of production from April 1948 to May 1949. Road-switchers were designed to deliver or pick up cars from yards across a railroad's system, including branch lines. As a result, they needed to have the power rating and cooling capacity to operate at road speeds, as well as being able to run in both directions when switching. Alco, Fairbanks-Morse, and Baldwin had all produced road switchers before EMD, and one of these, Alco's RS-1, would go on to have the longest production run of any diesel-electric locomotive in the U.S. (we have an RS-1 in our collection, Savannah River Plant No. 106). In 1947, branch lines made up 80% of U.S. rail mileage, so this was a market EMD could not ignore!

EMD 567B

The 567B engine was used on EMD's F3-F7 units, as well as the GP7.

The company's response, the GP7, was a product of lessons learned from the BL2, as well as borrowings from its competitors. It mimicked Alco's RS series car body design, with the long hood accommodating the engine, generator, and other equipment and the short hood providing facilities for the crew. The narrow hood allowed gangways with grab rails, greatly improved visibility for the engine crew, and better manoeuvrability for the switching crew. By the time the GP7 went into production, Alco had already produced its second road-switcher model, the RS-2, and EMD matched its 1500 hp rating with a 16 cylinder 567B engine.

After promotion of three demonstrator units, Nos. 100, 200 and 300, the GP7 proved highly popular, and EMD could barely keep up with the initial demand, even after opening a second assembly plant in Cleveland, OH. Of the 2,734 units built between October 1949 and May 1954, 2,615 were for U.S. railroads, 112 were for Canadian railroads, and 2 for Mexican railroads. Only five cabless GP7B units were built, all for the Atchison, Topeka and Santa Fe Railway in 1953.

ARR 1834

No. 1834 in Fairbanks, AK, in March 1973. Note the large box-like hatch on the rear
high hood covering the "winterizing kit." Photo courtesy of Daniel Napoliello.

No. 1804 was delivered as No. 1834, one of twenty GP7s bought by the U.S. Army in 1951 (Nos. 1821-1840). They were built with high front hoods, small, 800 gallon fuel tanks, no dynamic brakes and switcher trucks of the type used on EMD's SW7.

In 1960, thirteen of the U.S. Army units, including No. 1834, were sold to the Alaska Railroad where they were equipped with "winterizing kits." These large, box-like structures fitted over the last roof blower contained a set of louvers that could be set to allow exhaust to vent directly into the air during summer or to direct the hot exhaust back down into the engine room to warm the compressor, alternator and other components in winter.

Five years later, the original high end front hood was chopped down. Larger fuel tanks were fitted, and the switcher trucks were swapped out with AAR Type B trucks from Alaska Railroad's RF1 units. (Originally built as three axle RSD-1 units by Alco, these had been converted for the Alaska Railroad in 1949-50 to two axle, shrouded-hood RF1 units by the Puget Sound Bridge and Dry Dock Co. in Seattle.)

ARR 1804

No. 1804 standing in the yard in Fairbanks, AK, in June 1978. Photo courtesy
of Keith Ardinger.

In 1976, No. 1834 was one of nine Alaska Railroad GP7s to be refurbished at the Illinois Central Gulf Railroad’s shops in Paducah, KY. Shortly after, it was renumbered 1804.

The first prototype rebuild of No. 1821 was carried out by Morrison-Knudsen in Boise, ID, but M-K was then outbid by the ICG for the next nine units. The work included overhauling the prime mover, increasing hp by 1000, installing new modular electrical systems and AAR-type control stands, and replacing the Westinghouse 24L brakes with 26L. The low hood was redesigned, and a new cab installed of the type used on Alaska Railroad's GP40 units, although slightly smaller. These were designed to protect the crew from the harsh winter weather, with inside heating and a single, small cab window on each side.

The ICG started rebuilding its own GP units at the Paduca shops in the early 1970s, but also carried out rebuilds for Conrail and the Rock Island, as well as the Alaska Railroad. Unofficially, the rebuilds are known as GP10 units, although rebuilt GP7s are also sometimes referred to as GP7u units.

ARR 1804

No.1804 and McCloud River No. 39 cresting the top of Algoma Hill with an eastbound
on one of the few trips the unit made over this railroad. Photo from the Travis Berryman

By 1988, No. 1804 had been sold to FSA Rebuilding of Pico Rivera, CA, and was standing off its trucks with its "winterizing kit" removed in a scrap yard at Klamath Falls, OR, along with No. 1810, originally Alaska Railroad No. 1821, the prototype unit rebuilt by the M-K shops. The two units were then bought by the McCloud River Railroad in 1989. Returned to operating condition in 1991, No. 1804 saw limited service on that railroad, largely because of its tendency to spray sparks and cause trackside fires when operating in dynamic-braking mode.

Dynamic braking uses the electric traction motors in the trucks of a railroad locomotive as generators to assist in slowing the locomotive. The generated electrical power is dissipated as heat in brake grid resistors (known as rheostatic braking), or the power is returned to the main supply (regenerative braking). Dynamic braking lowers the wear of friction-based braking components, and regeneration can also lower energy consumption. The electrical energy produced by the motors in rheostatic braking is dissipated as heat by a bank of onboard resistors, and large cooling fans are needed to protect them from damage. Modern systems have thermal monitoring, so if the temperature of the bank becomes excessive, it will be switched off, and the braking will revert to friction only.

NIS 1804

Above, No. 1804 as it appeared in "Under Siege 2: Dark Territory." Photo taken by Vincent Porreca.
Part of the John Barnhill Collection.

On July 1, 1992 parent company Itel Rail sold the McCloud River Railroad to the newly created McCloud Railway Company, although Itel retained ownership of No. 1804. McCloud Railway then bought No. 1804 sometime in early 1993, but did not keep it long, as it had been resold to Nevada Industrial Switch by late spring 1993.

NIS had an active locomotive leasing and resale business, and leased No. 1804 to Corn Products in Stockton, CA. It also appeared with No. 1810 in "Under Siege 2: Dark Territory," the 1995 sequel to "Under Siege" starring Steven Seagal. The film is set on board a passenger train traveling through the Rocky Mountains from Denver to Los Angeles that is hijacked by terrorists.

Both locomotives were in their NIS colors but were lettered as "Grand Continental." They were operated by Southern Pacific crews, and No. 1804 was the lead unit.

NIS 1804

Above, No. 1804 starring in "Lethal Weapon 4." Photo copyright Steve Crise/

After filming, both GP7s went into storage in Exeter, CA.

In 1997, No. 1804 was sold to the Santa Clarita Railroad, a movie prop company in Saugus, CA. The following year it returned to the screen still sporting its NIS livery, but with the "Grand Continental" name removed, in "Lethal Weapon 4." This buddy-cop-martial-arts-action-thriller directed by Richard Donner, starred Mel Gibson, Danny Glover, Joe Pesci, Rene Russo, Chris Rock and Jet Li. No. 1804 was shot on location in downtown Los Angeles at the Los Angeles River and Union Pacific crossing on North Main Street plowing into one of the villains' cars. After filming, No. 1804 worked for a short time on the Pacific Harbor Lines in Los Angeles.

We bought No. 1804 from the Santa Clarita Railroad. It was shipped "dead" (i.e. without power) by train to Miami in December 2002 along with ex-Pennsylvania Railroad EMD E8 No. 5794, painted as Florida East Coast No. 1854, to join our collection. Painted in Atlantic Coast Line colors, No. 1804 is currently the workhorse of the museum, is regularly used to position museum rail equipment, and often gives cab rides on the property on weekends.


Status: On Display, Restored, Operational.
Acquisition Date: December 2002.
Built: EMD 1951 / Rebuilt: ICG 1976.
Serial: 15704.
Weight: 246,000 pounds.
Length: 55 feet 11 inches.
Height to Top of Cab: 14 feet 6 inches.
Horsepower as Built: 1500 / Rebuilt: 1600.
Engine: 567B 16 cylinder.
Generator: GM-D12.
Traction Motors: Four GM-D27B.
Trucks: Two 4-Wheel.
Truck Wheelbase: 9 feet.
Wheel Diameter: 40 inches.
Configuration: B-B.
Air Brake as Built: Westinghouse 24L / Rebuilt: 26L.
Compressor: Gardner-Denver WBO.
Starting Tractive Effort: 65,000 lbs @ 25%.
Continuous Tractive Effort: 40,000 lbs @ 9.3 mph.
Top Speed: 65 mph.

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