RACK RAILWAYS. 95 



respectively, both on the standard gauge, and shewing that the 

 cost of this work, on the former line, was only 76*6% (mark the 

 decimal) of that on the latter. But such comparisons as these as 

 well as those on which so much ink has been wasted, and which 

 are so frequently turning up with regard to the gauge and other 

 questions, are, I think, not of much value, unless we know much 

 more of the details than the writers ever give us, and even if we 

 had every possible detail their application to widely different local 

 circumstances would probably mislead us seriously. 



Comparisons, deduced from trials, between rival garbage 

 destructors, pumps, oil engines, etc., etc., are being constantly 

 put before the profession, but are very misleading as a rule, for 

 the reason just given. There was a trial, some years ago, between 

 a compound and a simple locomotive, for which a special length 

 of double line of railway was set apart. The two engines were 

 provided with the same class of fuel and water, and ran side by 

 side at the same time along the parallel roads, with the same 

 speed, load, grades, curves, and wind resistance, and yet with all 

 this, as nothing was said about the experience, ability, or even 

 temper, of the respective drivers, on which the economical working 

 of a locomotive so much depends, the results as to fuel consump- 

 tion etc. could not be regarded as absolutely decisive. Moreover 

 if severer grades, or other circumstances not met with in the trial, 

 were encountered, the results might have been reversed. So, in 

 the Hartz Mountain and Semmering case, where the other con- 

 ditions were nothing like so similar, we ought to know all about 

 the delicate question as to whether the respective traffic and loco- 

 motive superintendents in each case were capable men or otherwise, 

 apart from all questions of grades or racks. Such a knowledge 

 might upset the whole calculation, and turn the exact figure 76 '6 

 into something very different, and possibly over to the other side 

 of the comparison. 



It is evident that the mechanical effort of raising a given weight, 

 to a given height, in a given time, is not affected by the adoption 

 of a rack, as it is not a power in itself but only a means of apply- 



