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Steam Locomotion in the 21st Century

The Recent History of Steam Locomotive Development

Steam Locomotive Development Background

A brief discussion of the development of the "modern" steam locomotive.
updated 13 February 2022


Stephenson's Rocket

While not the first steam locomotive, this particular engine is the first example that pointed the way for further development. Built in Newcastle at the Forth Street Works of Robert Stephenson and Company in 1829, Rocket was the first steam locomotive to incorporate the features which became standard on the vast majority of steam locomotives built afterwards- (1) a firetube boiler with firebox at the rear and multiple firetubes (2) draft produced by directing the steam exhaust through a nozzle and up the exhaust stack, and two outside-mounted cylinders.  .

American Type 4-4-0 at the Mason Machine Works, 1873

This locomotive presents a very common type in the United States from 1850-1900, the 4-4-0. While obviously a great advance in styling and size compared to the Rocket pictured above, there is very little fundamental advance in this locomotive built 44 years later.  These locomotives were nevertheless very successful, and were widely used in both passenger and freight service.

                                2-8-0 No. 1272
1910 Frisco 2-8-0

This 2-8-0 built in 1910 illustrates another major advance in steam locomotive development:  the addition of superheating.  Superheating raised the temperature of the steam after it had left the boiler proper, increasing its energy content and greatly increasing the locomotive's efficiency.

While steam locomotives were still the primary railroad around the world, steam development reached two distinct pinnacles: U.S. locomotives were supreme in size and absolute power, and in mechanical durability. French locomotives, under the guidance of Andre Chapelon, attained the highest ratings for thermal efficiency, fuel economy, and power-to-weight ratios. Unfortunately, the excellent mechanical developments devised in the U.S. and the thermodynamic developments devised in France saw only limited applications outside of their respective countries. Other nations contributed many improvements, but the final steam locomotive developments in the U.S. and France had the greatest impact on steam locomotive performance.

U.S. locomotives were unmatched for size and brute power anywhere in the world. Since fuel was cheap (coal or heavy oil) and trackage was sturdy to support heavy engines, the "brute force" design philosphy was used. Consequently, the frames, cylinders, axles, and bearings of these engines were subject to incredible forces. Engines were required to run long distances without change and the minimization of routine maintenance was desired. While thermodynamic improvements were made, emphasis in design was placed on maximum power and durability.

Up until the 1930's, locomotive frames consisted of hundreds of parts which had to be machined and hand-fitted to form a rigid assembly. Cylinders were cast in separate pieces which had to be machined, bolted together, and precision-fitted to the frames to ensure a tight fit. In service, bolts would work loose regularly, requiring almost constant maintenance to maintain the frames and cylinders in proper alignment. By the 1930's, the Commonwealth Steel Corporation had perfected steel casting to such a degree that it became possible to cast the entire frame for a steam locomotive in one piece. This could include the main frames, cylinders, various brackets, and even air reservoir cylinders into a single casting. In combination with roller bearings developed by Timken and SKF, and self-adjusting wedges developed by Franklin, the cast bed frame greatly reduced running gear maintenance on modern U.S. steam locomotives.


Atlantic Coast Line No. 1808

from the H. L. Broadbelt collection

This locomotive was pretty typical of "modern" U.S. steam locomotive engineering practice. It incorporates the main ideas of Lima's Super Power concept, roller bearings from Timken, and a Commonwealth cast engine bed. Additional refinements include mechanical lubrication to numerous wear points and Baldwin "disk" drivers which were stronger and allowed better balancing than standard spoked driving wheels. While there were some promising developments in U.S. steam design after this stage, none achieved wide-spread acceptance and engines of this general arrangement remained the high water mark for steam in the United States.

Outside of the U.S., by far the most revolutionary steam locomotive design engineer was Andre Chapelon of France. He achieved amazing results through the systematic rebuilding of existing steam locomotives. Chapelon's chief focus was on streamlining the steam passageways within the locomotive to minimize losses. Most locomotive designed up to his time had been accomplished through "trial and error" methods. Chapelon carefully analyzed the losses in the steam circuits of locomotives and applied proper engineering to design improvements to minimize these losses. Chapelon realized that all parts of the steam circuit were important, and paid particular atention to exhaust system design, developing the Kylchap exhaust stack. By optimizing the steam circuit, increasing steam pressure and superheat, and improving the mechanical components of his locomotives, he greatly improved their performance. His compound engines achieved the record thermal efficiency for conventional steam locomotives (more than 12%) and achieved power-to-weight ratios not equalled anywhere else.

                    Orleans 4-8-0

Paris-Orleans Railway 4-8-0

While Chapelon's accomplishments were well-known in Europe, scant attention was payed to his accomplishments in the U.S. The designers of the New York Central S-1 Niagras appear to have been the exception, incorporating some suggestions from Chapelon in the steam circuit. On the other hand, Chapelon had visited the U.S. and was well aware of U.S. accomplishments.

After World War II, Chapelon began the development of the next generation of French steam by heavily rebuilding an existing 4-8-2 into a compound 4-8-4. From this effort, he proposed a series of 3 cylinder compound locomotives which would incorporate all his thermodynamic improvements, along with cast bed frames, roller bearings, and Franklin self-adjusting wedges. Unfortunately, France pursued a policy of electrification and steam locomotive development was stopped. Apart from a few engines which he designed for export to Brazil, Chapelon's role as a steam wizard had ended.

Thierry Stora has an incredible web page devoted to Chapleon's efforts. For details on Chapelon's amazing locomotives, go to the The French Compound Steam Locomotives Page.

After more than 120 years of continuous progress, world steam locomotive development practically stopped in 1950. Prior to this time, steam design had seen almost continuous progress ever since the 1830's. The size, power, efficiency, and complexity of steam locomotives increased. Reliability was improved and servicing requirements were reduced. Beginning in the late 19th century, the first challenge to steam rail power appeared in the form of electric locomotives. However, except in limited areas, electric locomotives never serious challenged steam mainly due to the high cost of installing the overhead wires (catenary) to supply power to the locomotives. In the 1930's, the first serious challenge to steam motive power appeared in the form of diesel-electric locomotives. Diesels had first appeared in the 1920's but by the late 1930's, General Motors "Electromotive" division (EMD) introduced the first diesel-electrics suitable for mainline passenger trains. Shortly afterwards, the first practical road freight locomotive appeared in the form of the EMD "FT". Diesel-electric locomotives had several advantages over steam power, and steam locomotive builders were slow to recognize that diesel locomotives were a serious threat to steam supremacy.

What were the advantages of the diesel? Follow this link for information: Steam vs. Diesel

World War II was both a blessing and a curse for steam builders. Steam locomotive development was frozen in most countries, but diesel production was also greatly curtailed. The Pennsylvania Railroad built its prototype 4-4-4-4 Duplex locomotives and later the S-1 direct drive steam turbine locomotive. By the end of the war, the diesel locomotive challenge was perfectly clear, but even at that late hour, most steam manufacturers were slow to react.

In the U.S., Baldwin was touting it's "Duplex" drive steam locomotives, which featured two sets of cylinders and running gear in a rigid frame. However, Baldwin was "hedging its bet" and simultaneously developing diesel-electric locomotives. ALCO seemed to have completely abandoned steam development and turned its efforts to designing mass-produced diesels. Lima was the only U.S. steam builder which seemed to have any serious interest in new steam. Lima was developing a new "double Belpaire" boiler which would significantly improve steam production. The double Belpaire boiler was intended to be used in conjunction with a new rotary cam, "long compression" poppet valve system developed by Franklin. Several designs were proposed, but a new wheel arrangement, the 4-8-6, was promoted highly. Unfortunately, U.S. railways showed very little interest in advanced steam designs with minor exceptions. By 1949, commercial steam locomotive production for domestic usage had ended.

In Europe and elsewhere, motive power production followed a similar trend. Chapelon and others in France developed advanced steam locomotives which showed great promise and had advanced designs on the drawing boards for post-war production. Construction of an advanced 2-10-4 was even underway. Unfortunately, France's leadership chose to electrify its railways. Other countries also rapidly moved to convert to diesel or electric railway power.

New steam locomotives were built after this time, but following the lead of the United States, most countries increasingly viewed steam as being outmoded and obsolete. Diesel locomotives and to a lesser extent electric locomotives replaced steam around the world.

Chapelon inspired one noted follower, Livio Dante Porta of Argentina, who until his death in 2002 worked diligently devising and overseeing improvements to steam locomotives around the world. Porta inspired his own series of followers, including David Wardale, Phil Girdlestone, Shawn McMahon, Nigel Day and others several of whom are still at work around the world continuing his work.

Porta and crew in front of RFIRT 2-10-2 # 110 "Santa Cruz"

(around 1960)
photo from the Richard Campbell collection
courtesy of Roberto Yommi

One thing a close study of the final steam efforts around the world shows: no steam locomotive ever built  included all the available proven techniques to maximize its performance in service. This fact, more than any other factor, is what lead to the downfall of world steam.

Time Line of Steam Development

The following provides a brief overview of steam locomotive development through the present day.

(most dates approximate)

  • 1800's
  • February1804- Richard Trevithick produces Penydarren, the first steam locomotive to run on rails.
  • 1830's
  • First practical steam locomotives developed
  • 1850's
  • Steam locomotive designs begin to be standardized
  • 1890's
  • First engines equipped with trailing trucks to allow larger, deeper fireboxes introduced.
  • 1900's
  • Beyer-Garratt type introduced
  • Mallets enter production
  • 1910's
  • Practical locomotive superheater introduced
  • Practical oil-fired engines developed
  • 1920's
  • Practical feedwater heaters and stokers introduced
  • Lima Superpower demonstrator "A-1" built
  • Cast steel locomotive engine beds introduced
  • simple articulated locomotives introduced
  • 1930's
  • Timken "Four Aces", first roller bearing equipped steamer, built
  • Chapelon achieves record steam efficiency in France
  • Practical diesel-electric locomotives introduced
  • duplex-drive steamers introduced in U.S.
  • 1940's
  • WWII freezes steam development in most countries
  • Franklin introduces poppet valves in the U.S.
  • Will Woodard, Lima engineer behind "Superpower", dies
  • Detailed steam/diesel comparison test on New York Central shows minimal cost difference in modern steam and new diesels
  • Chapelon constructs 242A.1
  • Lima 4-8-6 demonstrator proposed but not built
  • Construction of next generation of French steam started, then killed in favor of electrification
  • Last commercially manufactured U.S. steam locomotives built
  • Porta begins experiments with gas-producer firebox
  • Radical steamer "Leader" tested in England
  • wide-spread dieselization begins in U.S. and elsewhere
  • 1950's
  • Last privately manufactured U.S. steam locomotives built
  • Steam/diesel comparison tests on N & W are a draw
  • Advanced STE (Jawn Henry) tried on N & W
  • Specialty steam parts manufacturers cease production
  • Most U.S. mainline steam ends
  • 1960's
  • Last mainline steam in U.S. ends
  • Mainline steam ends in England, France, many other countries
  • Porta develops gas-producer combustion system (GPCS)& other refinements
  • 1970's
  • steam cutbacks around the world
  • Chapelon dies
  • "oil crisis" causes resumed interest in coal usage
  • Wardale oversees steam improvements in South Africa
  • 1980's
  • China continues steam locomotive production
  • Numerous locomotives restored to excursion service in the U.S.
  • Steam resurrected in Zimbabwe
  • ACE 3000 Project Announced
  • Other "new steam" projects announced
  • First ACE attempt dies
  • ACE resurrected
  • Second ACE attempt dies
  • ACE fails to interest China in production
  • Regular mainline steam ends in South Africa
  • 1990's
  • Chinese announce plans to end steam
  • Mainline steam ends in India
  • Many restored U.S. excursion steamers moth-balled
  • Steam resurrected in Sudan
  • New steamers built in Switzerland
  • Porta works to develop steam in Cuba
  • New steamers proposed for Australia
  • "A1" 4-6-2 under construction in the UK; other full-scale reproduction steamers proposed
  • 2000's
  • 5AT Project begun in the UK
  • L. D. Porta dies
  • First Lempor installation in U.S. (Mt. Washington Cog Railway)
  • More Lempor installations in U.S. (Grand Canyon Railway, Union Pacific)
  • Efforts to re-introduce steam on the RFIRT
  • A1 new construction 4-6-2 completed in the UK; enters excursion service
  • 2010's
  • 5AT Project cancelled
  • Advanced Steam Traction Trust formed in the UK
  • Pennsylvania T1 Project in US
  • More New Steam Projects in the UK
  • 2020's
  • Increased interest in the use of bio-coal fuel

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