Defect detection need

There were many early useless efforts of rail defect detecting device development in the late 19th century. Serious train derailments, which were blamed on transverse fissures, were increasing. One of them occurred in 1911, in Manchester, New York, killing 29 and seriously injuring 60. Another killed 21 and injured over 100 near Victoria, Mississippi, in October 1925. The need for dependable rail inspection became apparent.

Sperry Rail Service Vehicle

First developments

Dr. Sperry began developing a method of locating internal rail defects in 1911. To build a railway test car he contracted with the American Railway Association in 1927. Construction on this first car began in June 1927. The body was metal-faced plywood, and was mounted on a Kalamazoo motor car bed. This car was towed by a larger motor car. After completion, it was delivered December 17, 1927, for performing tests. An operator, lying flat on his stomach as he was moved along on a hand car, held a "search unit" against the rail. Both fissures were found, but serious difficulties were encountered during the test. This method also posed problems due to uneven rail surfaces.

Detection methods

Dr. Sperry and his staff discovered a new principle for detecting transverse fissures in 1928, called the "induction method."^[2] It also found split-heads and other invisible defects. While a major advancement, this method had its limitations: it did not function properly at the end of each rail where angle bars and bolts held two succeeding rails together, or where two rails converged such as at switch points. These rail parts had to be examined individually by a hand-held ultrasonic scanner.

The induction system was augmented by mobile semi-automated ultrasonic inspection equipment in 1960. Today, Sperry performs both induction testing and ultrasonic testing with its rail service vehicles.^[2]

Later redevelopments of 101 unit

It would appear that the induction-based testing method equipment replaced the original magnetic equipment on Sperry Rail Service 101. Even though it was completed almost ten months before, the car was rejected by the American Railway Association's Rail Committee until October 2, 1928. After a test run on September 27, 1928, by Dr. Sperry and his research engineer H.C. Drake, it began testing on the New York Central under ARA supervision. The test with the modified 101 was so successful that construction on SRS 102 began almost immediately.

Sperry Rail Service Corporation runs tests

The original plan of Dr. Sperry was to build and sell the rail detector cars, along with the testing services, to the railways. However, the railways were reluctant, so Sperry decided to sell the rail inspection service only.^[2] It would lead to more consistent testing, which is done by skilled and experienced personnel.

• At this point Sperry Rail Service Corporation was created to market the testing service. The first commercial test was accomplished in November, 1928, on the Wabash Railway over a 130-mile (210 km) section of track between Montpelier, Ohio, and Clarke Junction, Indiana performed by SRS 102. The expansion of service put two more SRS cars into operation. In the early 1930 four cars were in service. By the end of 1930, Sperry Rail Service Corporation's fleet increased to ten cars.
• The fleet continued to expand along with the served area. In addition to services on U.S. railroads, the SRS cars also traveled to Canada, Mexico and overseas. Smaller railways could not afford their own rail detector car, with their limited use. However, the New York Central and the Union Pacific did own such rail detection cars. Many Sperry cars were created by rebuilding existing railway cars, particularly doodlebugs.^[2]

More information about the types of defects that can be found by the Sperry rail car is detailed in this document.^[3]