thumb|300px|Lima builder's plate, 1918
thumb|300px|Concept for a Lima Shay Museum in Lima, Ohio, 2005
thumb|300px|Site for Lima Shay Museum Concept, 2005

'''Lima Locomotive Works''' was an American firm that manufactured Baltimore & Ohio's Cincinnati-Toledo main line and the Nickel Plate Road main line and shops. The company is best known for producing the Shay geared logging steam locomotive, and for being the home of William E. Woodard's "Super Power" advanced steam locomotive concept - exemplified by the prototype 2-8-4 Berkshire, Lima demonstrator A-1.

== History ==

In 1878 James Alley contracted the Lima Machine Works to build a steam locomotive that Ephraim Shay had designed. In April of 1880, Lima rebuilt Ephraim Shay's original design, using vertically side-mounted pistons mounted on the right, connected to a drive line on the outside of the trucks. The Shay was geared down to provide more slow-moving pulling ability for use in the lumber industry. The first Shay locomotive was built in 1880 and was such a success that many people in the lumber industry wanted one. To accommodate the new demand for the locomotive Shay licensed the right to build his locomotive to the Lima Machine Works, which expanded and began to ship Shay locomotives to lumbermen across the frontier. Two years later, locomotives were the main product being produced by the Lima Machine Works, which would produce over 300 locomotives during the next ten years. 

After a serious fire, a new shop was opened in 1902 and Shay production continued.  However, as railroads began to recognize that speed was as important as efficiency in freight service, the Shay was rendered obsolete.  With no option, Lima began constructing conventional steam locomotives, and also began producing other heavy machinery such as steam cranes and railroad rotary snow plows.

== Super Power ==  

Success returned to Lima in the 1920s with the new concept of "Super Power" developed by Lima's mechanical engineer William E. Woodard. By making a number of significant changes to maximize a steam locomotive's capacity to generate and utilize steam, Woodard was able to make such locomotives significantly more powerful and faster.  He did this by starting in 1922 with the H-10 experimental heavy 2-8-2 design for the New York Central (Michigan Central 8000) and applying both relatively new science (the Cole ratios) every efficiency-enhancing tool available - a larger firebox, increased superheat, a feedwater heater, improved draughting, higher boiler pressure, streamlined steam passages and a trailing-truck booster engine, and by applying limited cutoff (the range of steam valve admission settings) to prevent locomotive engineers from using excessive steam at starting.  The 2-8-2 thus produced was demonstrated to be 26% more efficient overall than its immediate predecessor, and the NYC bought 301 copies.  

A large increase in firebox area (from 66 square feet on the H-10 to 100 square feet on the A-1) characteristic of his work necessitated adding another axle to the trailing truck, creating the 2-8-4 wheel arrangement.  Built in the spring of 1925, the first Berkshire (a demonstrator owned by Lima) was dubbed the A-1.  It quickly proved to be a whopping 26-30% more efficient than the H-10!  After a highly successful series of tests in the mid-1920s it was sent around the country to make the idea of "Super Power" known.  The first forty-five were purchased by New York Central's subsidiary Boston & Albany following initial road testing across the summit of the Berkshire Hills, and the 2-8-4 wheel arrangement came to be known as the "Berkshire" on most railroads.  The prototype itself was later sold to the Illinois Central as part of an order for 50 similar locomotives.  Woodard summed up "Super Power" by defining it as "horsepower at speed".  Previous design principles emphasized tractive effort (pulling ability) rather than speed.  By 1949 some 613 Berkshires had been constructed for North American service, of which twenty are preserved - at least two in operating condition (NKP 765 and PM 1225), both Lima products.    

There were at least three successive waves of "Super Power".  The first began with NYC 8000 and the A-1, and included Missouri Pacific 2-8-4s and Texas & Pacific 2-10-4s.  These locomotives had conventional 63" driving wheels.  In 1927, the Erie Railroad took delivery of a "second-phase" Berkshire with 70" driving wheels, capable not only of great power but higher speed; in turn, this design evolved into the Chesapeake & Ohio T-1 2-10-4s of 1930, with 69" driving wheels.  The "third-phase" of the later 1930s and war years can be identified with locomotives such as the homebuilt N&W 2-6-6-4s, C&O/Virginian 2-6-6-6 and virtually all American 4-8-4s.  Boiler pressures rose as high as 310 lbs/sq.in.; thermic syphons added to the firebox and combustion chamber added 8% to the efficiency of the boiler; roller bearings appeared on main axle boxes and sometimes on running gear.  And the "Super Power" concept had extended to other builders such as Alco (the Union Pacific Big Boy) and Baldwin (the Santa Fe 5001- and 5011-class 2-10-4s).  The four-wheel trailing truck became the standard for large locomotives (ie. 4-8-4, 2-10-4, 4-6-6-4, 2-8-8-4).

== Decline ==

La société '''Lima Locomotive Works''' a été une société américaine de construction de matériels ferroviaires de 1877 à 1958.

== Histoire ==
rigth|thumb|300px|Plaque de constructeur Lima Locomotive Works.
rigth|thumb|300px|La GS-4 N° 4449 du [[Southern Pacific Railroad|Southern Pacific, construite par LIMA en 1941, et préservée en état de marche par l'Oregon Rail Heritage Foundation à Portland.]]
Elle doit son nom à la ville de Lima (Ohio) où elle a été créée.

A la fin du XIXe siècle la '''LIMA Machine Works''' était une entreprise qui fabriquait du matériel pour l'industrie forestière, dont les célèbres locomotives Shay à moteur vertical et transmission par cardans, qui étaient des machines dédiées à cette activité.

Puis au début des années 1900, la '''LIMA Locomotive & Machine Company''' se mis à produire des locomotives pour les chemins de fer américains, en 1911 elle devient la '''LIMA Locomotive Corporation''', et en 1916 la '''LIMA Locomotive Works Incorporated'''.