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Pro(;kess in Locomotive Testing. 



By AV. F. M. Goss. 



It is now fourteen years since the initial steps were talcen to install at 

 Purdue University a locomotive testing plant. Plans wbicli were then 

 formulated were rapidly worked 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 bo run at any speed and under 

 any load, its action being controlled in precisely the same manner as when 

 in actual .<^ervice, 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 pr;;ctieal value of the Purdue plant was at once recognized. It 

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

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

 a locomotive on the lo.id 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 had 

 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 acciu*ate methods in observing the performance of a locomotive 

 which had lireviously been elaborately developed for testing stationary 

 engines. Mechanical engineers and superintendents of motive power 

 visited the laboi'atory to witness the operation of the Purdue testing plant, 

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

 Other plants were soon proposed. In 1S96 the Chicago &: Northwestern 

 Railway Company equipped its Chicago shops for locomotive testing, and 

 more recently. Columbia University has supplied a locomotive testing 

 plant for its engineering laboratory. Other institutions have plants in 

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

 8— A. OF SciE.NCE, '03. 



