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Sperry Rail Service

This is an 'un-official' web site about


Last revised June 26, 2010

This site was reviewed in Canadian Railway Modeller Train 10 Track 5 (April 2001)

For information about the services offered by Sperry Rail Service, as well as employment,
please visit the 'official' SPERRY RAIL SERVICE web site, or contact them at:-
46 Shelter Rock Road
Danbury, Connecticut 06810
United States
Phone: (203) 791-4500
FAX: (203) 797-8417


The rail flaw detector car was invented by Dr. Elmer A. Sperry. Born October 12, 1860 in Cortland, NY,
Dr. Sperry passed away June 16, 1930. In his lifetime, he founded eight manufacturing companies and took out over 400 patents. Having a keen interest in machinery and electricity from an early age, Sperry developed dynamos and arc lamps. He established Sperry Electric Mining Machine Company in 1888 to manufacture electric rotary and chain undercutting machines he had invented for the mining industry.

In 1890, Dr. Sperry began to apply his vast knowledge and skills to transportation. First he designed an electric industrial locomotive and motor transmission machinery for streetcars, founding the Sperry Electric Railway Company in Cleveland, Ohio. He soon sold this to the General Electric Company. In 1894 he turned his interest to the building of electric automobiles powered by his patented storage battery.

Sperry's greatest invention was the gyrocompass. He set up his Sperry Gyroscope Company in Brooklyn, NY,
in 1910. He extended the gyro principal to the guidance of torpedoes, gyropilots for steering ships and for stabilizing airplanes.

To railways and railfans, the name Sperry is more likely to be associated with the Sperry Rail Detector car. Early efforts in the late 1800's to develop a rail defect detecting device had proved unsuccessful while serious train derailments, blamed on transverse fissures, were on the increase. In addition to previous derailments, one occurred in Manchester, New York, in 1911, killing 29 and seriously injuring 60, while another killed 21 and injured over 100 near Victoria, Mississippi in October 1925. It was apparent that a dependable rail inspection device was needed.

In 1923, Dr. Sperry began work on developing a method of locating internal rail defects. In 1927, he contracted with the American Railway Association to build a rail test car. Construction on this first car, numbered 101, began in June 1927. It consisted of a metal faced plywood body mounted on a Kalamazoo motor car bed which was in turn towed by a larger motor car. Following completion, it was delivered December 17, 1927 for testing.
An operator, laying flat on his stomach, held a 'search unit' against the rail as he was moved along on a hand car. Fissures were found during the tests, but serious difficulties were also encountered. This method also had problems due to uneven rail surfaces.

Dr. Sperry and his staff worked around the clock for several months, until in 1928, they discovered a new principal for detecting transverse fissures, the 'induction method'. In addition to detecting transverse fissures, the induction method also found split-heads and other invisible defects. This system was used until 1960 when semi-automated ultra-sonic equipment was added to the Sperry fleet. Ultra-sonic rail testing was first offered in 1949, equipment being mounted on a motor car, with hand held inspection made at each joint.

It would appear that equipment based on the induction method replaced the original magnetic equipment on 101. Although it had been completed almost ten months earlier, the car was not accepted by the Rail Committee until October 2, 1928 following a test run on September 27, 1928 by Dr. Sperry and H. C. Drake, his research engineer. It soon began testing on the New York Central under the supervision of the ARA. So successful was the test with the modified 101 that construction on SRS 102 was begun almost immediately.

Dr. Sperry's original plan had been to build and sell the rail detector cars to the railways, as well as selling the testing service. However, the railways were reluctant to purchase the cars outright so Sperry decided not to sell the cars but rather the service only. In this way, testing would be consistant as it would be done by skilled, experienced, personnel.

To market the testing service, Sperry Rail Service Corporation was created. The first commercial testing was done in November 1928, on the Wabash Railway over a 130 mile section of track between Montpelier, Ohio and Clarke Junction, Indiana, with SRS 102. The service soon spread and Sperry put two more cars into operation. At the beginning of 1930 four cars were in service. By the end of that same year, the fleet had increased to ten cars.

The fleet continued to expand as did the area served. In addition to providing service to U.S. railroads, the Sperry rail cars also travelled to Canada, Mexico, and even overseas. Smaller railways could not justify the expense of having their own rail detector car, which would see limited use, unlike the New York Central and the Union Pacific who did own such cars. Many Sperry cars were created by rebuilding existing railway cars, in particular, Doodlebugs. In most cases, the rebuilt cars bore little resemblance to the original.

Link to an article originally published in the November 1954 Southern Railway employee magazine, TIES.
How Do I Look, Doc? (courtesy Southern Railfan web site.)

On August 29, 2002, it was announced that Sperry Rail Service had acquired Harsco Corporations's rail flaw detection (RFD) group. Harsco's track maintenance division, known as Harsco Track Technologies (HTT), is located in Sperry's home town of Danbury, CT. With the acquisition, Sperry's rail flaw detection fleet increased by 30 trucks. Harsco was previously known as Pandrol Jackson Technologies, and before that Dapco.

(Last revised February 28, 2010)
(Last revised June 26, 2010)


SRS 117 SRS 119 SRS 123 SRS 124 SRS 125 SRS 127 SRS 128 SRS 129 SRS 130 SRS 131 SRS 132 SRS 134 SRS 136
SRS 117 SRS 119 SRS 123 SRS 124 SRS 125 SRS 127 SRS 128 SRS 129 SRS 130 SRS 131 SRS 132 SRS 134 SRS 136
SRS 137 SRS 138 SRS 140 SRS 141 SRS 141 SRS 142 SRS 143 SRS 143 SRS 146 SRS 147 SRS 148 SRS 149 SRS 403
SRS 137 SRS 138 SRS 140 SRS 141 SRS 141 SRS 142 SRS 143 SRS 143 SRS 146 SRS 147 SRS 148 SRS 149 SRS 403
SRS 451 SRS 805 SRS 811 SRS 815 SRS 821 SRS 824 SRS 827 SRS 873 SRS 964 SRS 965 SRS 972
451 Series SRS 805 SRS 811 SRS 815 SRS 821 SRS 824 SRS 827 SRS 873 SRS 964 SRS 965 SRS 972

Latest additions/revisions are shown with red fleet number.

[click on thumbnails for larger view]

Scanned images of Sperry Rail vehicles are solicited for use on this site. Full credit will be given.
These may be forwarded via e-mail by clicking on the Sperry car below.


Sperry Rail Service-Track Inspection (North East Rails website)
Sperry Rail Service Cars (Joe Shaw's Rail Images website)
Sperry Rail Service Photos (Barp website)
Sperry Rail Service Photographic Rooster
Mark Wayman SRS Collection
Sperry Rail Service Pix

A number of videos showing Sperry Rail Service cars and Hi-Rail trucks can be found on You Tube.
Once on the You Tube site, simply do a search for Sperry Rail Service.


  • Detecting Track Defects, - page 21-37
    Railway Maintenance: The Men and Machines That Keep the Railroads Running by Brian Soloman,
    MBI Publishing Co., St. Paul MN, 2001, ISBN-13: 978-0-7603-0975-9 / ISBN-10: 0-7603-0975-2
  • Guardian of The Rails, Trains Magazine October 1941 page 28
  • Roster of Sperry Rail Service, Railroad Magazine January 1970 page 66
  • Sperry and Speno on the Gee-Mo, Gulf, Mobile & Ohio Historical News Issue No. 116 pages 10-22
  • Sperry Detector, A Quarterly Report published by Sperry Rail Service - various issues
  • Sperry Detector Car, Railroad Model Craftsman October 1952 page 15
  • Sperry Rail Detector Car, Railroad Model Craftsman May 1940 page 10
  • Sperry Rail Detector Car #135, The Railyard Local July 2004 page 6.
    (The Railyard Local is a publication of the Danbury Railway Museum)
  • Sperry Rail Inspection Car, Model Railroader January 1952 page 42
  • Sperry Rail Service 1928 - 1968, The Bulletin - N.R.H.S. Vol. 33 No. 6 1968 page 7
    (issue includes an all-time roster of Sperry cars as a separate enclosure)
  • Sperry Testing Track in Sweden and Norway, Canadian Rail #471 July-August 1999 page 118
  • Sperry trucks track troubles deep inside rails, Trains Magazine February 2006 page 20
  • Sperry's Big Yellow Fleet, Railroad Modeler May 1979 page 22
  • Sperry's Golden Anniversary, Railfan January 1979 page 27
  • The Day the Sperry Car Replaced the Budd Car, Canadian Rail #468 January-February 1999 page 18
  • The Sad Little Story of the FCD, Extra 2200 South February-March 1969 page 16
  • The Self-sufficient nomad, Trains Magazine January 1963 page 44
  • The Sperry Rail Car, South Jersey Magazine Winter 1988 - four page article
  • What An Inventor Thinks About: Visit to Philadelphia Centennial Exposition Inspired the
    Late Elmer A. Sperry to Engage in a Remarkable Career of Invention in Many Fields,
    The Deleware and Hudson Railroad Bulletin November 15, 1930 page 347


  • Hallmark Models Inc., of Dallas Texas, imported two runs of a brass HO scale model based on SRS 136.
    The first run was produced in Japan while the second run was made in Korea by Dong Jin. It represented
    the car when it had a tubular-type pilot and powered by an EMC prime-mover (Winton). This model is often available on eBay. A review of the Japanese version appears in the Trade Topics column of the June 1970
    Model Railroader on page 20. Of interest, the price was $52.95 US in 1970.
  • Model Railroader January 1952 page 42 - Sperry Detector Car - Plans for SRS 136
  • Railroad Model Craftsman June 1956 page 56 - Sperry Detector Car - Plans for SRS 118
  • Porthole Productions (c/o Robert Fabris, 3626 Morrie Drive, San Jose, CA 95127), produced an HO scale
    cast urethane body shell for SRS 136 designed to fit on a Life-Like FA chassis.
    (See Model Railroader September 1997 page 8 for a picture of the shell).
  • In the winter of 2000, Walthers released a plastic HO scale model of a Sperry Rail Car in three different paint schemes and numbers plus an undecorated version.
    (A review of the model appeared in Model Railroader Magazine July 2001 page 22).
  • Father Nature Railroad Specialties (John W. Kreider, 600 Pine Rd., Palmyra, PA 17078), produced an
    N scale Sperry Rail Service car shell in resin which was designed to fit on a Life-Like FA chassis.
  • An unpainted metal kit (body only) of a Sperry Rail Service truck is available in HO scale from Custom Finishing. Details here. This item is also available from Walthers. The recommended paint for this model is Testors Model Master B-1707 Chrome Yellow FS13538.

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This is NOT an official Sperry Rail Service web site, nor does it have any connection with Sperry Rail Service.
I have no connection with Sperry Rail Service, however, should you contact Sperry Rail Service,
please mention the fact that you found out about them through this web site.

TrainNet Web Gem Award
Sept. 21, 2002
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