885
steel to a very great extent. According to C. P.Sandberg, mild steel rails are weakened 80 per cent,by notching in the flange, and hard steel rails 97 percent, by square cornered notches j inch deep, and95 per cent, by round cornered notches. Hackneystates that a Great Western double-headed rail withno holes stood a blow of 1 ton falling 20 feet, while,when a hole was punched through the web, it brokeunder the first blow with a 3 feet fall; and whenthe hole was drilled it stood a 2 feet fall, but brokewith the second blow from 4 feet. Price Williamshad an elaborate series of tests, conducted byKirkaldy, upon the same point (see paper on“Permanent Way of Railways,” Inst. C.E.), andarrived at the conclusion that “the ultimate stressof steel rails punched cold in the ordinary way was65-39 per cent, of the ultimate stress of unpunchedrails, whereas the ultimate stress of the drilled railswas 98'68 per cent, of that of the undrilled rails.”This was, of course, with a gradually applied strain.Williams has also investigated with great care thewear of steel rails, and has proved conclusively thata rail rolled from a cogged ingot is stronger than arail of the same steel from a hammered ingot.
Two of the first steel rails ever used on a railwaywere laid on the London and North Western line atCamden Town; and, according to Price Williams’calculation, one of these carried 5,152,856 tons foreach one-sixteenth of an inch worn down, the other8,474,576 tons for one-sixteenth of an inch wear;while on an average the Crewe rails require 9,370,777tons to roll over them before they lose one-sixteenthof an inch in thickness; while some steel rails onthe Great Eastern Railway have withstood 27,000,000tons, and on the Great Northern Railway, 30,000,000tons for each one-sixteenth of an inch wear. Itappears that the character of the ground has moreto do with the wear of a steel rail than anythingelse. If the ballast be continually wet, the rail getsground out very rapidly, while in dry situations,where dust and dirt do not aid the grindingaction of the wheels, they are extremely durable.Williams assumes 43 years as the average life ofsteel rails. The following extremely interestingtable (XVIII.) of the wear of rails on the GreatNorthern Railway is also due to Williams, andis highly instructive. The whole paper will wellrepay a close study:—
TABLE XVIII.—SUMMARY OP TABLE SHOWING THE AMOUNT OF WEAR AND TONNAGE OVER STEEL RAILS IN AND NEARMAIDEN LANE AND COPENHAGEN TUNNELS, TOGETHER WITH A CHEMICAL ANALYSIS OP THE RAILS.
No. 9.
Copenhagen Tunnel.(Down.)
No. 17 .
Maiden LaneTunnel (up).
No. 18.
Maiden Lane Tunnel.(UP.)
No. 21.
North of CopenhagenTunnel (up).
No. 22.
North of CopenhagenTunnel (up).
No 23.
North of CopenhagenTunnel (up).
No. 24.
North of CopenhagenTunnel (up;.
Tonnage.
96,824,000
Tonnage per l-16thWear.
15,129,000
Tonnage.
40,329,000
Tonnage per l-16thWear.
5,251,000
Tonnage.
40,329,000
Tonnage per l-16tliWear.
8,402,000
Tonnage.
63,868,000
Tonnage per l-16thWear.
7,676,000
Tonnage.
63,868,000
Tonnage per l-16tliWear.
9,283,000
Tonnage.
59,638,000
Tonnage per l-16thWeai\
15,531,000
Tonnage.
59,638,000
Tonnage per l-16thWear.
31,061,000
CHEMICAL ANALYSIS BY RILEY.
No. 9.
No. 17.
No. 18.
No. 21.
No. 22.
No. 23.
No. 24.
Maiden Lane
Maiden Lane
North of Copen-
North of Copen-
North of Copen-
North of Copen-
Tunnel (down).
Tuunel (up).
Tunnel (up).
hagen Tunnel (up).
hagen Tunnel (up).
hagen Tunnel (up).
hagen Tunnel (up).
0-336
0*331
0-296
0*302
* 0-538
0-340
10-270
0-034
0-029
0-029
0-034
0-040
*0-062
t 0-020
t 0-038
0-090
0‘051
*0-096
0-059
0*055
0-051
0-125
0-186
0-344
0-162
o-iii
* 0-242
t o-ioo
99-408
99*451
99-637
99-632
99-249
99-223
99-475
0*338
0*353
t 0-245
t 0-245
0-461
*0-475
0-259
Copper,.
* 0-032
0-020
0-020
t 0-018
0-022
0-028
0-025
100-311
100-460
100/422
100-489
100-480
100-425
100-200
Maximum percentage. f Minimum percentage.
Smith of Barrow has likewise investigated thequestion of wear of steel rails, and has come tothe remarkable conclusion that it is not the hardestrails, or those highest in carbon, which wear thelongest. This conclusion seems to be confirmedby the previous table, although contrary to whatmight have been expected. Further experimentsand observations upon these points would be desir-able. The following table (XIX.), by Smith, is thefoundation for his deductions.
A comparison of the tensile strength and elasticityof mild steel, as compared with the best Yorkshire brands of iron, such as Lowmoor and Bowling,shows the great superiority of the former in everyrespect; and as steel can now he made of thoroughly
reliable and regular quality at about half the costof this far-famed material, there would appear tobe no object in adhering to the more expensivematerial; and as prejudice wears away there isevery reason to expect that steel will supersedeiron for shipbuilding, bridge construction, andboiler work, as completely as it has already super-seded iron for railway bars.
Much greater progress is being made in the useof steel in France and Germany than in England,the Governments of these countries lending valuableassistance to the manufacturers: 40, 50, and even100 ton castings are now common in France , andTerre Noire is making guns and armour plates fromannealed castings without hammering or rolling.