Soe a i 
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ON RAILWAY BAR CORROSION. — 103 
Onexamining this table weare enabled todeduce the following results, viz.— 
lst. The absolute abrasion during the whole period of 1460 days on the 
six rails is 59,175 grs. avoir, 
2nd. The absolute corrosion on the six rails in use, and exposed to traffic 
in same time, is 24,450 grs. avoir. 
8rd, The ratio of abrasion to corrosion on the rails in use is therefore 
nearly in the ratio of 59°2 to 24°5, or about as 2°4 to 1. 
4th. The absolute corrosion of the six out of use and not travelled over 
was 33,250 grs. avoir. 
5th. The ratio of the abrasion of the rails in use to the corrosion of the rails 
out of use is therefore nearly as 59°2 to 33°3, or about as 1°44 tol, or 17 tol. 
6th. The absolute difference between the corrosion of the rails in use and 
out of use is 8800 grs. avoir, Hence 
7th. The ratio of the corrosion of the rails in use is to that of the rails out 
of use as 24°5 to 87:9, or nearly 88, or in round numbers as 3°14 to 1. 
Here again then we have corroborated the fact of a real difference in cor- 
rosion due to traffic, and again we find it a decreasing one as compared with 
the former experiments. 
We now proceed to give the amount of traffic on the Dalkey Atmospheric 
Railway during the four years of these experiments, as deduced from the 
records of the Company by Mr. Bergin at my request. 
The whole traffic up and down passed over the experimental rails. 
Traffic of the Dalkey Atmospheric Railway from 7th January 1845 to 23rd 
November 1848. 
No. of trains. No. of coaches. No. of passengers. 
86,972 296,048 949,636 
The average proportion of the classes of 2nd and 3rd class carriages is one 
of equality, one of the latter being always a piston carriage ; and the average 
weights are— Piston carriage.......:.. 5 tons 1 ewt. 
Second class coach ...... eae ode ear 
Third class coach........ BE A has 
And taking the passengers at 14 to the ton to allow for luggage, we have for 
the weights in the above time— 
1,166,155 tons of dead weight in trains 
67,831 tons of passengers. 
Total.... 1,233,986 tons of gross load. 
But the line was stopped on the 23rd November 1848 for repair, and 
worked by alocomotive. ‘The estimated traffic for this period up to January 
7, 1849, is thus :— Tons. 
288 locomotives at 10 tons.......,.. =2880 
214 second class coaches. .......... 760 
914 third class coaches ............ 706 
4274 passengers, 14 per ton.......... 305 
Dotabsvdiph jeri 2. 4651 
Which, added to the foregoing, gives for the whole period of traftic— 
1,233,986 
4,651 
1,238,637 tons 
divided into 86,972 + 288=87,260 trains. The average weight per train is 
therefore only 142 tons. 
The total load transferred per annum on the average was 309,659} tons. 
_The half of this=154,8293 tons was therefore transferred over each length 
of rail annually. 
