EMD "SD18" Locomotives: Data Sheet, Specs, Roster

Last revised: August 27, 2024

The SD18 was Electro-Motive's third entry in its six-axle, "Special Duty" line. The model was tailored towards branch line work where its lightweight trucks and six axles could more easily negotiate these secondary corridors.

It was the final normally aspirated variant in the initial series which included the SD7, SD9, SD18, and SD24 (EMD's first turocharged six-motored locomotive). Its model 567D1 prime mover and 1,800 horsepower offered the greatest - non-turbocharged - output up until that time.

Ironically, the SD18 sold better to foreign lines than domestically with the Korean National Railroad and Central Railway of Brazil acquiring 60 of the 114 units produced.

The locomotive was also EMD's first six-axle model offered with a low, short hood. The previous SD7 and SD9 were not cataloged with this option although some railroads modified theirs with this configuration.

Photos

Reserve Mining SD18 #1231, SD9's #1226 and #1229, a rare SD28 (#1233), and an unidentified switcher are seen here in service near Babbitt, Minnesota on May 2, 1970. Jim Jeffery photo. American-Rails.com collection.

History

The SD18 was the third model in EMD's six-motored catalog. Outwardly, it was nearly identical to the earlier SD9, including the marker lights' location near the edge of the tapered short hood.

In his book, "EMD Locomotives," author Brian Solomon notes the builder - for a brief period between the late 1950s and early 1960s - began listing models by their horsepower ratings.

Why this practice began - and ultimately was discontinued - is unknown although the SD18 was once such model denoting such. Its model 567D1 prime mover - one of the engine's final variants - boasted 1,800 horsepower and standard Flexicoil trucks.

Spotting Features

The nearly identical SD18 and SD9 are very difficult to differentiate. Perhaps the easiest spotting feature is the low, short hood - first offered as an option with the SD18. Two buyers requested this feature, Reserve Mining (pictured above) and Chesapeake & Ohio.

The C&O's units were perhaps the most interesting. In addition to their low, short hood - the early variants of which featured a slight tapering towards the pilot - Chessie requested theirs be equipped with Trimount trucks from trade-in RSD5s.

The C&O - which had purchased a total of twenty-six such units from Alco in 1952 - was never pleased with these units. The railroad ultimately wound up with a total of nineteen SD18s. The big six-axle brutes enjoyed many years in service and several even made it into Chessie System paint before their retirement.

Missabe SD18 #189 and an SDM power another long string of ore jennies through Iron, Minnesota on August 15, 1994. Wade Massie photo.

Reception

Despite sales reaching only 54 units domestically, another 60 were purchased by foreign railroads. Interestingly, this time Southern Pacific - a big buyer of the SD7 and SD9 - was not interested in EMD's latest six-axle locomotive. However, the railroad would return for future models.

SP was immediately sold on the SD7 and SD9, acquiring some 193 examples - 43 SD7s and another 150 SD9s. In fact, the railroad tested demonstrator #990 and ultimately purchased this unit.

The company found these sure-footed locomotives perfectly suited for tackling the steep grades, sharp curves, and light rail found on its many secondary lines in Oregon.

American railroads which purchased the SD18 included:

Bessemer & Lake Erie ( 851-857)
Chesapeake & Ohio Railway (1800-1818)
Chicago & Illinois Midland Railway (60-61)
Duluth, Missabe & Iron Range (175-193)
Reserve Mining (1226-1232)

Foreign lines acquired the bulk of production including; Rede Ferroviária Federal, Sociedade Anônima (RFFSA) of Brazil (3401-3445) and the Korea National Railroad (6001-6015).

Data Sheet and Specifications

Entered Production	4/1960 (Duluth, Missabe & Iron Range #175-180)
Years Produced	4/1960 - 3/1963
Engine	567D1
Engine Builder	GM
Horsepower	1800
RPM	835
Cylinders	16
Length	60' 8"
Height (Top Of Rail To Top Of Cab)	15' 0"
Width	10'
Weight	300,000-360,000 Lbs
Fuel Capacity	1200 Gallons
Air Compressor	Gardner-Denver
Air Compressor Model	WBO
Air Brake Manufacturer	Westinghouse
Air Brake Schedule	6BL
Trucks	C-C
Truck Type	Flexicoil
Truck Wheelbase	13' 7"
Wheel Size	40"
Traction Motors	D47 (6), GM
Primary Generator	D22, GM
Steam Generator (Optional)	Vapor-Clarkson (Model OK4625)
Auxiliary Generator	Delco
Alternator	D14
MU (Multiple-Unit)	Yes
Dynamic Brakes	Yes
Gear Ratio	62:15
Tractive Effort (Starting)	97,500 Lbs at 25%
Tractive Effort (Continuous)	67,500 Lbs at 9.3 mph
Top Speed	65 mph

Production Roster

Total Built = 114

Owner	Road Number(s)	Serial Number(s)	Order Number	Date Built
Duluth, Missabe & Iron Range	175-180	25779-25784	5615	4/1960
Duluth, Missabe & Iron Range	181-193	25785-25797	5616	4/1960
Reserve Mining Company	1226-1227	26211-26212	5628	11/1960
Reserve Mining Company	1228-1230	26656-26658	5630	5/1961
Reserve Mining Company	1231-1232	26665-26666	5631	12/1962
Chicago & Illinois Midland	60	26668	5632	12/1961
Chicago & Illinois Midland	61	27392	5638	6/1962
Chesapeake & Ohio	1800-1818	27598-27616	7630	1/1963-3/1963
Bessemer & Lake Erie	851-857	27721-27727	5644	9/1962
Rede Ferroviária Federal, Sociedade Anônima (Central Railway of Brazil)	3401-3445 (SD18M)	26520-26564	702854-702898	9/1961-12/1961
Korean National Railroad	6001-6009	28373-28381	700735-700743	8/1963
Korean National Railroad	6101-6106	28382-28387	700744-700749	9/1963

Production of the locomotive had ended by March, 1963. EMD actually had better sales with the SD24 produced at the same time, which sold more than 200 examples (including B units). This continued a trend across the industry of utilizing increasingly more powerful models in standard road service.