RAILWAY CONSTANTS. 223 



resolved into components parallel and perpendicular to the mo- 

 tion of the train. The component parallel to the motion would 

 then be treated as a wind directly favourable or adverse. The 

 lateral component acting against the extensive surface usually- 

 presented by the side of the train, would have the effect of press- 

 ing the flanges of the opposite wheels against the rails. This, 

 combined with the effect of the conical form of the tires, would 

 have a tendency to impart to the carriages an oscillating motion 

 between the rails, causing the flanges alternately to strike the 

 i*ails, and thereby to produce a resistance the amount of which 

 it would be diffiicult indeed to reduce to general methods of cal- 

 culation. 



It appears, therefore, most desirable that experiments for the 

 exact determination of the mean amount of resistance to railway 

 trains should be made when the atmosphere is calm, but it is 

 rarely that this condition can be obtained. In its absence, the 

 results of the experiments can only be regarded as approxima- 

 tions, more or less precise as the disturbing causes exist in a 

 less or greater degree. 



It was not easy to find on the railways which have been com- 

 pleted inclined planes in convenient situations in all respects 

 suited for the plan of investigation which was contemplated. On 

 the whole, however, it seemed that the most eligible were the 

 Whiston and Sutton inclines on the Liverpool and Manchester 

 Railway, and a series of inclines between Madeley and Crewe 

 on the Grand Junction Railway. 



The summit of the Whiston plane is at about nine miles from 

 Liverpool, and the plane falls at nearly an uniform rate of 1 in 

 96 towards Liverpool for a distance of 2700 yards. From the 

 foot of the plane the line rises at the average rate of 1 in 936 for 

 a distance exceeding the range of the experiments. 



A stake marked was placed at the summit of the plane, and 

 twenty- seven other stakes, marked successively 1, 2, 3, &c., di- 

 vided the whole length of the plane into spaces of 100 yards. 

 The distance from the 27th stake, which marked the foot of the 

 plane, to the 24th mile post was 150 yards, and the line from 

 that point towards Liverpool was divided by quarter-mile posts, 

 the levels of which were taken. 



The inclined plane thus divided by the twenty-seven stakes 

 was perfectly straight from the summit to the 24th stake. At 

 that stake curves having a radius of 3300 yards commenced, 

 which terminated at the 24^ mile post, a point about 900 yards 

 from the foot of the plane. From that point to a point 220 

 yards beyond the 24f mile post from Manchester the line was 

 straight, and from the latter point to 370 yards beyond the 25th 



