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 CHAPTER X INSPECTION AND TESTING testing work in connection with locomotives may be divided into two main categories— (a) The testing of the materials of which the engine is constructed. (b) Testing and trials of finished locomotives. Testing and Inspection of Materials. This is done at the works of the various manufacturers of the plates, bars, axles, tyres, etc., who provide facilities in the shape of testing machinery, in which specimens cut from the material are broken and their physical behaviour noted. The railway companies, if the materials are for use in this country, or the consulting engineers, if the engines are being built for abroad, have their representatives or inspectors at the works of the manufacturers, to pass the materials for acceptance if the tests prove satisfactory, or reject them if they do not come up to the specified requirements.

Tensile Tests. The most important physical test is known as the tensile test. A piece of the plate is machined to definite rectangular or circular form and dimensions, and placed in the jaws of the testing machine. The specimen is