LOCOMOTIVE ENGINE AND RAILWAY GRADIENTS. 177 



power of the engine, the assistant engine under these cir- 

 cumstances becomes absolutely necessary ; on the other 

 hand, where the load is duly proportioned to the power, 

 and that power so nicely balanced as to have full command 

 over the resistance, we may then with great benefit, and no 

 inconsiderable economy, dispense with every description of 

 auxiliary force. In railway traffic these facts are worth 

 knowing, and are fully borne out by the results thus ob- 

 tained in working one of the largest and most difficult 

 inclines in the kingdom. 



In the experiments thus recorded^ it may. be interesting 

 to ascertain how far they correspond with the results arrived 

 at on the Hunt's Bank and Halifax inclines, and the com- 

 puted resistances as given in the preceding tables. In 

 cases of the latter it is estimated, that a locomotive engine 

 of 16 inch cylinders would, at a speed of 33 miles an hour, 

 raise a load of from 35 to 37 tons up an incline of 1 in 40. 

 Now, in the case of the Accrington incline, if we compare 

 the power of the single engine with 15 inch cylinders, 

 which raised a load of 40 tons at the rate of upwards of 17 

 miles an hour up gradients, some of them steeper than 1 in 

 40, and allow for the retarding influence of curves, we shall 

 then have a duty nearly equivalent to that in the table, if 

 not approaching to the experiments made on the Hunt's 

 Bank incline, where a much greater load was carried at a 

 considerably reduced rate of speed.. Viewing the subject 

 in this light, and allowing for the increased pressure attained 

 in experimental trials, compared to that of the regular 

 working of the trains, we may reasonably conclude, that 

 the diffijrences are not so great as appearances at first sight 

 would indicate. 



In conclusion I would observe, that, notwithstanding the 

 great improvements and increased powers which for the last 

 fifteen years have been introduced into the locomotive en- 

 gine, it would appear that we have not as yet arrived at that 



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