Jackshaft (locomotive)
A
Jackshafts were first used in early steam locomotives, although the designers did not yet call them by that name. In the early 20th century, large numbers of jackshaft-driven electric locomotives were built for heavy mainline service. Jackshaft drives were also used in many early gasoline and diesel locomotives that used mechanical transmissions.
Steam locomotives
The
In a conventional steam locomotive, the crankshaft is one of the
Several locomotives have been built with horizontal cylinders driving a crankshaft directly above the rear
Early designers of steam turbine locomotives did not understand the need for reduction gearing or sprung suspensions.[11][12] Once these problems were understood, jackshafts emerged as one alternative for linking the output gearbox of the turbine to the driving wheels. Giuseppe Belluzzo, of Italy, was granted several US patents on variations of this idea.[13][14][15] Alternatives to jackshaft drives included use of a quill drive with the turbine above the drive axle, or a combination of a quill drive with a gearbox suspended horizontally between a locomotive driving axle and the turbine shaft.[16][17]
Electric locomotives
Many early electric locomotives were also equipped with jackshafts. A general survey of electric locomotive design from 1915 shows 15 distinct jackshaft-drive arrangements out of 24 distinct locomotive designs.
Some early locomotives used small diameter DC
Examples include the
Continuing development of electric motors made them smaller, and by World War II, most new and made jackshafts obsolete.
Internal combustion locomotives
When Baldwin first began building internal combustion locomotives in the first decades of the 20th century, they used a 2-speed transmission from the gasoline engine to a jackshaft.[1] Baldwin's early internal combustion locomotive patents covered the use of both
The first Baldwin internal-combustion locomotives used an 0-4-0 configuration and weighed from 3.5 to 9 tons, but by 1919, a 25-ton 0-6-0 configuration was available.The
Suspension movement
A difficulty with coupling rod drive from a jackshaft is the need to allow for vertical suspension movement of the axles. Several mechanical arrangements have been used to allow this.
Long horizontal rods
The simplest arrangement is to use long coupling rods, running horizontally. A large vertical movement at the wheel end gives rise to only a small horizontal movement at the jackshaft drive. For a diesel-mechanical locomotive this can be compensated for by horizontally compliant mounting of the transmission. The heavy
This arrangement is common for slow speed diesel shunters, but not usually for main line speeds. The Swedish D-lok of 1925 did use it, with two motors geared to a single jackshaft with short rods between two driving axles of a 1-C-1 layout.
Slotted rods
Vertical sliding bearings in hornblocks would allow movement, but these must be designed carefully or else the force exerted through the rods would be wasted in simply sliding this bearing back and forth. Such sliding joints must be arranged to allow suspension travel, but so that the rod force is always at right angles to the slideway.
The ten-coupled Italian
Conceptually similar linkages were used for the Swiss Ce 6/8II crocodiles. As these had only a single traction motor at each end, the triangular frame was also carried by a blind, unpowered, jackshaft. It was slightly inclined, as the motor jackshaft was above the wheel axis.
Winterthur diagonal rods
Most of the Swiss crocodile classes used the Winterthur diagonal rod or Schrägstangenantrieb (German) design instead.
These locomotives were articulated, with one large traction motor on each of the two bogies at each end. The jackshaft was thus placed above and between the driving wheels. To maximise the length of its drive rod and reduce its angulation, this was connected near to the furthest driven axle. The coupling rod between those axles was 'triangular', with an additional bearing mounted on its top edge, taking the thrust of the jackshaft drive rod. Unlike most connecting rods, this allows it to be mounted in the same plane as the coupling rod bearings. This reduces the overhung lengths of the crankpins and their bending loads.
This arrangement is simple and robust, but does not give a perfect geometry and so is known for its creaking noises and rough running, particularly if the rod bearings become worn. For the Swiss locomotives: well-maintained, powerful locomotives running at slow speeds over steep gradients, this was an acceptable design. It did not however make many inroads into fast passenger services.
Ganz and Kandó linkages
Some of the more complicated linkages used for express locomotives were the Ganz, Kandó or Bianchi linkages. These were in the form of an inverted triangle, reaching down from the high-mounted motor jackshaft to the wheel axle line.
The Ganz form was used on the Hungarian-built Les Belles Hongroises 2BB2 400 locomotives for the French PO. This had four links forming the triangle, with the two upper vertices mounted to the locomotive frame (through a short swinging link) and to the jackshaft crankpin. The lower apex of the triangle contained a short triangular link, which linked the sides of the triangle to the wheel crankpin. By tilting this link, the suspension movement was absorbed.[27] This linkage ran well at speed and as it was composed entirely of pivoting joints with no sliding, there was no lost motion. It was however complex, heavy and unbalanced.
The Kandó linkage was similar in compensation, but the upper vertices were carried by a pair of motor jackshafts.
The only one of these linkages with a widespread or long service life was the symmetrical, and better-balanced, Bianchi linkage, used in Italy.
References
- ^ a b General Construction, Baldwin Gasoline Industrial Locomotives Baldwin Locomotive Works Record, No. 74, 1913; pages 7-9.
- ^ J. Snowden Bell, Chapter I: The "Grasshopper" and "Crab" Engines -- type 0-4-0, The Early Motive Power of the Baltimore and Ohio Railroad; page 19.
- ^ Ross Winans, Locomotive Steam-Engines, U.S. patent 308, granted July 29, 1837.
- ^ Links in the History of the Locomotive, No. XI, The Engineer, June 10, 1881; page 432, with a large illustration.
- ^ Joseph Tomlinson, Address by the President, Proceedings Institution of Mechanical Engineers, Vol. 41 (1890); pages 181-202.
- ^ J. Snowden Bell, Chapter IV: The Eight-Wheel Connected Freight Engines -- Type 0-8-0, The Early Motive Power of the Baltimore and Ohio Railroad Sinclair, New York, 1912; pages 55-86, see particularly Fig. 22 on page 57.
- ^ Ross Winas, Locomotive, U.S. patent 3,201, granted July 28, 1843.
- ^ 402, Alfred Greig and William Beadon, The Commissioners of Patents Journal, No. 2770 (July 20, 1880); page 167.
- ^ Roberf F. McKillop and John Browning, John Fowler Locomotives, Sugar Cane Transport, Light Railway Research Society of Australia, 29 Feb. 2000.
- ^ Australian Sugar Heritage Centre, [www.sugarmuseum.com.au/the-museum/], 2010.
- ^ Johann Stumpf, Locomotive with Steam-Turbine Drive, U.S. patent 855,436, granted May 28, 1907.
- ^ Joel B. Dumas, Steam Turbine for Locomotives, U.S. patent 1,010,878, granted Dec. 5, 1911.
- ^ Giuseppe Belluzzo, Steam Turbine Locomotive, U.S. patent 1,638,079, granted Aug. 9, 1927.
- ^ Giuseppe Belluzzo, Steam Turbine Locomotive, U.S. patent 1,666,590, granted Apr. 17, 1928.
- ^ Giuseppe Belluzzo, Turbine Locomotive, U.S. patent 1,887,178, granted Nov. 8, 1932.
- ^ Fredrik Ljungström, Turbine-Driven Locomotive and Similar Vehicle, U.S. patent 1,632,707, granted June 14, 1927.
- ^ Frank L Alben, Steam-Turbine Locomotive, U.S. patent 2,386,186, granted June 10, 1943.
- ^ Albert S. Richey and William C. Greenough, Electric Locomotives, Electric Railway Handbook, McGraw Hill, 1915; pages 579-587, figures 48-71 on pages 584-586.
- ^ A. T. Dover, Chapter XVII: Electric Locomotives, Electric Traction: A Treatise on the Application of Electric Power to Tramways and Railways, MacMillan, New York, 1917; pages 355-409.
- ^ Archibald Ehle, Internal-Combustion Locomotive, U.S. patent 951,062, granted Mar. 1, 1910.
- ^ Archibald H. Ehle, Internal-Combustion Locomotive, U.S. patent 1,018,889, granted Feb. 27, 1912.
- ^ Internal Combustion Locomotives, Baldwin Locomotive Works Record, No. 95 (1919); pages 3-33.
- ^ War Activities of the Baldwin Locomotive Works, Baldwin Locomotive Works Record, No. 93, 1919; pages 3-21.
- ^ "12031 1960s Springs Branch". Archived from the original on October 7, 2011. Retrieved July 5, 2009.
- ISBN 0-86288-351-2.
- ^ Modern Locomotives (2000), pp. 34–35.
- ^ Modern Locomotives (2000), pp. 50–51.