RAILROAD CONSTRUCTION 
323 
life because a tie which has been spiked four times becomes so 
weakened that it often breaks under the rail especially if the ends 
of the tie are not well ballasted. When spurs are taken up only 
two spikes in each crosstie may l)e pulletl, one on the outer side 
of one rail and the other on the inner side of the opposite rail. 
The tie may then be forced to one side and removed. When the 
track is relaid, the spikes in the tie are pulled slightly, the rail 
slipped under the spike heads and the latter then driven tight 
against the rail flange. The average annual tie renewals on 
southern logging operations average about two hundred per year. 
Crossties of special length are required for a switch. A set 
of timbers for a single switch ranges in length from 9 to 15 feet 
and the number varies with the frog; e.g. a number 8 frog 
requires 47 and a number 10 frog 56. 
These are often sawed out in the mill. 
On rough track the long switch ties 
may be replaced by two standard-length 
ones. 
Steel Rails. — Rails are classified ac- 
cording to their weight in pounds per 
linear yard, and those of a given weight 
are now made of a uniform size. 
The chief parts of a rail are the head, Fig. 107. — A Standard 
the web, and the flange base. The head 
contains 42 per cent of the metal, the web 
21 per cent and the flange 37 per cent. 
Rail Head, a, the head. 
b, the web. c, the 
flange base. 
WEIGHTS AND DIMENSIONS OF STANDARD RAILS 
Rail part 
A 
B 
CandD 
E 
F 
G 
II 
Iff 
Weight per yard in pounds 
Dimensions in inches 
2 
21 
2i 
2i 
2^ 
2tV 
2 7 
3 1 
1 
33 
ST 
IB 
3^ 
B? 
2 
6 5 
3H 
31 
4A 
4i 
4tV 
4f 
2 1 
1 1 
83 
49 
2 5 
13 
3U 
1^ 
32 
g? 
J'S 
If, 
m 
2tV 
2H 
2H 
21 
•m 
ItV 
H 
Hi 
I3V 
1^"^ 
m 
27 
3? 
935 
187 
