Diesel Locomotives, Extinguishing The Fire Of Steam

Diesel locomotives, technically known as diesel-electrics, came into widespread use following development of Electro-Motive Corporation’s (later, General Motors' Electro-Motive Division) EA/EB design, first tested on the Baltimore & Ohio Railroad (B&O) in 1937.  The motive power's genesis, however, dates back even further to the World War I period when an early switcher model entered service.  The industry remained skeptical of the diesel for many years, relegating it to secondary status while steam remained the preferred choice for main line assignments.  

This changed after General Motors successfully demonstrated the diesel's viability during testing of its FT freight design in 1939.  The demonstrator set toured the country, convincing skeptic after skeptic that diesels were not only efficient and reliable but could also outperform the iron horse.  Today's newest models offer even great advancement, heavily computerized to monitor almost every aspect of a locomotive while in service.  As a result, the "old school" ways in which an engineer operated theirs has been taken away through technological improvements in models like the SD70ACe-T4 and ES44AC.

A diesel-electric's mechanics are rather straightforward although it is commonly mistaken that the diesel engine propels the locomotive.  This is not the case.  While the engine is the prime mover the energy it creates drives an electric generator, which in turn powers the traction motors found within the locomotive’s trucks.  The latter are responsible for turning the wheels and propelling the unit forward. The engine, itself, has no connection to the actual motion.  In essence, the diesel is an electric locomotive with its own power plant.  What is the difference?  A true electric is provided power via electricity through either overhead catenary or third-rail while a diesel-electric carries its own (engine) on board.   This motive power type has been around in one shape or form since 1917 when General Electric began testing an experimental model utilizing a GM-50 prime mover (a V-8 diesel engine designed by GE).   A year later it launched formal production of these 225 horsepower machines; the line was largely considered a failure although a few were sold; one to the Jay Street Connecting Railroad (#4), another to the city of Baltimore and finally one to the U.S. Army.

American Locomotive Company (Alco)

A History Of The American Locomotive Company, Alco 

Alco's Canadian Arm, The Montreal Locomotive Works 

Alco's First Cab Design, The Experimental Black Maria 

Competing With EMD's F Model, The FA Series 

The Beautiful PA Series

The Century Series, Alco's Final Road-Switcher Catalog

The Early DL Design, The Company's Initial Cab Series

The RS-1, The Road-Switcher Is Born

The RSD-1, For The Army

The Joint EMD/Alco MRS-1 Road-Switcher For Military Service 

The RS-2, Following Its Predecessor

The RSC-2 Variant

The RS-3, Alco's Best-Selling Road-Switcher

The RSD-4, Continuing The Six-Axle Design

The RSD-5, Higher Sales Than Its Predecessor

The RSD-7, Alco Struggles In The Road-Switcher Market

The RS-11, Unable To Keep Pace With EMD

The RSD-12, Another Poor Seller

The RSD-15 "Alligator"

The RS-27, Striving For Success

The RS-32, Another Failure

The RS-36, Last In The Road-Switcher Series

The C-415, A Most Unique Design

The C-420, Introducing The "Century" Series 

The C-424,  A More Powerful But Unsuccessful Model 

The C-425, Still Lagging Behind 

The C-430, The Final Four-Axle Century 

The C-628, The First Six-Axle Century 

The Big C-630 Line

The C-636, Powerful Yet Unpopular 

The C-643DH Diesel-Hydraulic, An Experimental For SP 

The C-855, A Beast Built For Union Pacific

The S-1, Alco Finds Success With The Switcher

The S-2, Continuing Strong Sales

The S-3, Another Moderate Success

The S-4, Yet Another Home Run

The S-6, The Final Standard-Model Switcher

The Intriguing T-6, "Transfer" Design

The Joint General Electric/Alco Gas Turbine Design

Undeterred by this experiment's lackluster performance the company pressed forward with a new design in 1923.  This latest trial carried GE electrical components, a prime mover from Ingersoll-Rand (capable of 300 horsepower), and a carbody provided through American Locomotive (Alco).  As the late historian Jim Boyd notes in his book, "The American Freight Train," the 60-ton boxcab was finished in 1924 and proved a success.  It eventually sold to the Central Railroad of New Jersey (#1000) where it spent many years in switching assignments around New York City.  Ironically, despite the company's pioneering ways it never launched its own formal locomotive line until the late 1950's.  It did remain involved, however, by partnering with Alco providing it components (such as traction motors) while also pioneering early electrification systems and locomotives.  In time, the Schenectady builder continued to lose market share against Electro-Motive, spurring GE to launch its own "Universal" line in 1959.  While a commercial success the series was not particularly reliable (many of these so-called "U-boats" had a lifespan of only a few decades).  Once more, GE did not give in and spent many years fine-tuning its design until it had overtaken EMD by the 1980's.

The early boxcabs are often credited as the first with a diesel engine although the very first railcar to utilize an internal combustion engine was the McKeen Car.  In Brian Solomon's book, "The American Diesel Locomotive," the idea for this concept came from William McKeen, Union Pacific's chief of motive power.  Even by the early 20th century railroads were attempting to cut costs on lightly patronized branch lines and UP's leader, the legendary Edward Harriman, approached McKeen in 1904 about developing a self-powered railcar for use on these secondary corridors.  After many tests at the Electric Railway Test Commission in St. Louis they came up with an aerodynamic design powered by a 100 horsepower, gasoline engine manufactured by early pioneer, Riotte.  The first unit, listed as #M-1 and given the name "Windsplitter," was completed at UP's shops in Omaha, Nebraska during March of 1905.  Following a refinement which featured a longer frame and marine engine (producing twice the horsepower), Harriman was impressed.  He allowed McKeen to setup production of the McKeen Railcar Company in 1908.

Baldwin-Lima Locomotive Works (BLW)

A History Of The Baldwin Locomotive Works 

The Lima Locomotive Works, A Future Baldwin Partner 

The Whitcomb Locomotive Works, A Division Of Baldwin 

The VO-660, Entering The Switcher Market 

The VO-1000, Baldwin's Top Sales Performer

The DS-4-4-660, Replacing The "VO" Series 

The DS-4-4-750, Offering 750 Horsepower

The DS-4-4-1000, The Final "DS" Series Model

The S-8, A New Model Of Switcher

The S-12, Baldwin's Final "Standard" Line Switcher 

The DT-6-6-2000, A Unique Design For Transfer Service

The RT624, The Final Transfer Variant 

The DRS-4-4-1500, The First Road-Switcher 

The DRS-6-4-1500, Struggling To Find Sales

The DRS-6-6-1500, The Most Successful In The "DRS" Series

The AS16, Unveiling The "Standard" Line

The AS416, Fighting To Maintain Market Presence

The Six-Axle AS616, The Most Successful "Standard" Line Model

The RS12, The Light Road-Switcher

The "Baby Face" DR-4-4-1500, Baldwin's First Cab Model 

The DR-6-4-1500, A Failed Design 

The DR-6-4-2000, Another Flop 

The RF16 "Shark," Offering Improved Sales 

The DR-12-8-3000 "Centipede," A Singularly Baldwin Design 

A History Of Baldwin's "Sharknose" Carbody 

The Company's First Carbody Design, The Unpopular "Baby Face" 

Early on McKeen was successful but soon ran into reliability issues and sales had flattened by 1912. While the "Windsplitter" had its issues other companies were triumphant (including GE and Electro-Motive) in producing a reliable railcar for branch line service, the so-called "Doodlebug."  Their achievements eventually led to the diesel-powered boxcab switchers mentioned above.  These early examples proved their worth in branch line and secondary assignments.  However, usurping steam's dominance in main line service was another matter entirely.  The venerable Baltimore & Ohio was always a technological trailblazer and with the diesel it was no different.  It holds the distinction as the first to utilize one for main line service, Electro-Motive's boxcab #50, manufactured in 1935.  Electro-Motive took this boxcab and upgraded its prime mover with a rugged General Motors model 567 while shrouding it within a sleek carbody.  This FT demonstrator A-B-B-A set, #103, began testing across the country in November of 1939.  As Brian Solomon notes in his book, "Electro-Motive E Units And F Units," it proved itself time again, such as on Southern Pacific's Tehachapi Grade where it outperformed SP and Santa Fe steamers (the AT&SF held trackage rights in this territory). 

According to David Morgan's article, "The Diesel That Did It," from the February, 1960 issue of Trains Magazine during their trials the locomotives traveled 83,764 miles on twenty Class I's in thirty-five states over an eleven-month period.  Many, like the Santa Fe and Southern Pacific, were so impressed they immediately placed orders.  Others, like New York, Ontario & Western purchased the model based on word-of-mouth.  It would take the diesel nearly fifty years to equal the horsepower output of a single steam locomotive during its technological height. However, diesels made up for this disadvantage in other ways. They required far less maintenance, including heavy overhauls, and could operate much further between refueling stops.  This meant diesels could spend more time on the road doing what they were designed for, paying the bills.  In addition, thanks to MU (Multiple Unit) technology a single engineer from the lead locomotive could control several trailing units, increasing the horsepower output per train.  As Mr. Solomon notes, while American Locomotive, General Electric, and Ingersoll-Rand spearheaded the diesel's development, it was General Motors/Electro-Motive which successfully mass-produced them for main line service.  GM had already entered the auto industry and recognized that durable internal mechanics coupled with a rugged prime mover (the model 567) could mean big business.  This led to cab designs packaged within an attractive carbody and the rest, as they say, is history.

General Electric (GE)

A History Of General Electric's Many Locomotive Models 

A Look At GE's First Road-Switcher Series, The Classic "U-Boat" 

The U18B "Baby Boat," The Light Road-Switcher 

The U25B, GE's Enters the Locomotive Market 

The U28B, Following Its Predecessor 

The Modestly Successful U30B 

The U33B, The Fourth U-Boat 

The U36B, Purchased Only By The SCL And Auto-Train 

The U23C, A Light-Powered Late-Era Design 

The U25C, The First Six-Axle 

The U28C, Adding Power 

The U30C, Providing EMD Competition 

The U33C, Driving Alco Out Of The Market 

The U36C, The Final Cataloged U-Boat 

The U50, An Experimental, 5,000 Horsepower Monster 

Another Experimental, Union Pacific's Enormous U50C 

The Joint General Electric/Alco Gas Turbine Design

The B23-7, Replacing The U-Boat 

The B30-7, Picking Up Sales 

The B36-7, Four Axles And 3,600 Horsepower 

The Popular Six-Axle C30-7, Looking To Supplant EMD 

The Powerful C36-7 

The "Super 7" Series Rebuild Program 

The B32-8 Series, Offering 3,200 Horsepower 

The B39-8 Variant, A Rare, Unsuccessful Design 

The B40-8/W, The Last Four Axle 

The Six-Axle, 3,900 Horsepower C39-8

The C40-8/W Series, Surpassing EMD 

The C40-9/W Variant

The C44-9W, Cementing Its Dominance 

The Popular AC4400CW, Designed For Drag Service 

The AC6000CW, Providing 6,000 Horsepower 

Continuing Its Reign, The Evolution Series 

General Motors’ Electro-Motive Division (EMD)/Electro-Motive Diesel

A History of General Motors' Electro-Motive Division (EMD), Today's Electro-Motive Diesel

EMD's Canadian Division, General Motors Diesel 

Early EMC Switchers: SW, SC, NW, NC 

The Interesting "Cow-Calf" Switcher Designs

The NW2, Offering Early Success

The SW1, Featuring The New 567 Prime Mover 

The SW7, Another Favorite

The SW8, Providing Slightly More Power

The SW9, Maintaining Strong Sales

The 900 Horsepower SW900

The SW1000, Showcasing EMD's Second-Generation, 645 Prime Mover

The SW1001 Variant, Fixing A Problem

The SW1200, Continuing EMD's Dominance

The SW1500, Another Bestseller

The MP15DC/AC/T Series, EMD's Last Switchers

A General History Of The Passenger E Series 

The Early EA/E1/E2 Models

The E3, Replacing The Winton With The 567

The Seaboard Air Line's E4

The Burlington's Sleek, Stainless-Steel E5

The E6, The First Production Passenger Model

Rock Island's Unique AB6, Designed For The "Rocky Mountain Rocket"

The Successful E7, Debuting EMD's Iconic "Bulldog Nose" Carbody

The E8, EMD's Continues Its Reign

The E9, Last In The Series

A Look At EMD's Popular Freight Line, The F Series 

The FT, Replacing The Steam Locomotive

The Rare F2

The F3, Cementing Diesel's Dominance

The F7, The Blockbuster Covered Wagon

The Passenger Model FP7

The F9, Closing Out The "Bulldog" Design

New Haven's Unique, Dual-Service FL9

The F40PH Series

The "Cowl" F45 Series

The Notorious SDP40F Passenger Variant

The BL2, The GP Series Predecessor

Great Northern's GP5

The GP7, Debuting An Icon

The GP9, Another Phenomenal Road-Switcher

The Versatile GP15 Series

The Modestly Successful GP18

The Rare RS1325

The GP20, Entering The Turbocharged Age

The GP30, Offering A Timeless Look

The GP35, Finding Continued, Second-Generation Success

The GP38 Series, EMD Hits The Mark Again

The Successful GP40 Series

The Unsuccessful GP50

The GP60, Last Of The Geeps

The Joint EMD/Alco MRS-1 Road-Switcher For Military Service 

The SD7, EMD's First Six-Axle Road-Switcher

The More Successful SD9, "Cadillac"

The SD18, A Late-Era First-Generation Model

The SD24, EMD's First Turbocharged Road-Switcher

The SD35, Growing Six-Axle Popularity

The SD38 Series, Featuring The New 645

The Blockbuster SD40/SD40-2 Series, The Gold Standard

The Powerful, 20-Cylinder SD45 Series

The SD50, Electro-Motive's Downfall

The SD60 Series, Attempting To Rebound

The Successful SD70 Series

The SD75M/I Variant

Conrail's SD80MAC

The 6,000 Horsepower, But Problematic SD90MAC

Electro-Motive's Latest Model, The SD70ACe

Odd/Unique Designs

B Units 

C&NW's Crandall Cabs 


DDA40X, "Centennial" 

Draper Taper 

Krauss-Maffei ML-4000 


Rock Island's AB6 


Tunnel Motors 

Wabtec Freight (Formerly GE Transportation)

An Overview Of Wabtec Freight

Notable Prime Movers

Alco's Model 244 

Alco's Model 251 

EMD's Model 567 

EMD's Model 645 

EMD's Model 710 

Truck Types

AAR Type A/B 

Blomberg Type A/M 



Related Companies/Designs

Davenport Locomotive Works 

Plymouth Locomotive Works

Other Reading


Gensets/Green Goats 

Rail Diesel Car, RDCs 


Notable Events/Programs

Norfolk Southern's Heritage Program 

Streamliners At Spencer 

Union Pacific's Commemorative Series 

Common Designs

The Switcher, Performing Yard Work And Other Light Duties 

The Cab Unit, The Era Of Streamlining

The Standard Road-Switchers, Tasked With Handling Heavy Freights 

The Unique Transfer Switcher Variant 

Diesels have come a long way from the EMC and Alco-GE-IR boxcabs of the 1920's.  Today's models, manufactured by Wabtec Freight (successor to General Electric) and Progress Rail (successor to EMD), are equipped with comfort cabs, air conditioning, and advanced electronics. During the early days there were more than just two builders.  After Electro-Motive opened a new motive power market many joined in, including Alco, Lima, Baldwin, Fairbanks-Morse, and later GE.  The former had been the longstanding "Big Three" steam manufacturers.   They had produced thousands of high-quality locomotives during their heyday but unfortunately could never make the successful transition to diesel technology.  Alco was the last holdout, finally closing in 1969.  Fairbanks-Morse was a bit of an outlier with a history tracing back to the 19th century.  It became a leader of the opposed-piston marine engine and decided to enter the diesel market during the 1940's.  Unfortunately, it couldn't establish a foothold after a decade and gave up (but is still in business today).  EMD never, truly recovered after losing its top spot in the 1980's, which led to its sale by General Motors in 2005.  Today, the corporate division has been dissolved altogether and Progress Rail only uses the company name for marketing purposes.  A testament to its first and second-generation models endures, however, as those built more than a half-century ago can still be found in revenue service today!

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