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PROiiREss IN Locomotive Testing. 



By W. F. M. Goss. 



It is now fourteen years since tlie initial steps were tal^en to install at 

 Purdue University a locomotive testing plant. Plans which were then 

 formulated were rapidly Avorked out, and in the fall of 1891, the completed 

 plant was put into operation. It consists of a mounting mechanism, 

 upon which any locomotive can be operated in much the same manner as 

 upon the road, while retaining its fixed position in the laboratory; and of 

 such accessory apparatus as is needful in measuring its power and in de- 

 termining its elHciency. A locomotive mounted upon the testing plant 

 can be tired as if upon the road and can be run at any speed and under 

 any load, its action bein^g controlled in precisely the same manner as when 

 in actual service, while its fixed position in the laboratory allows the 

 attachment of delicate apparatus, and permits great accuracy in the 

 methods employed in studying its performance. 



The practical value of the Purdue plant was at once recognized. It 

 had long been understood that in testing a steam engine, the maintenance 

 of constant conditions was of prime importance, whereas tlie operation of 

 a locomotive on the road is attended by a great variety of changes in 

 conditions which affect its action. Again, upon the road, so great are the 

 limitations governing the attachment of apparatus that observations Imd 

 necessarily been of a very elementary sort. Difficulties in testing arising 

 from these and other causes were entirely overcome by the advent of the 

 testing plant. By its use it became possible to apply to the locomotive 

 the same accurate methods in oljserving the performance of a locomotive 

 which had previously been elaborately developed for testing stationary 

 engines. Mechanical engineers and superintendents of motive poAver 

 visited the laboratory to witness the operation of the Purdue testing plant, 

 from many parts of our oAvn country, and from several foreign countries. 

 Other plants were soon proposed. In 1896 the Chicago & Northwestern 

 Railway Company equipped its Chicago shops for locomotive testing, and 

 more recently, Columbia Univer.sity has supplied a locomotive testing 

 plant for its engineering laboratory. Other institutions have plants in 

 ..contemplation. Meanwhile, the Avork of the Purdue plant has proceeded 

 8— A. OF Scie.ncp:, "03. 



