194 BULLETIN 111, U. S. DEPARTMENT OE AGRICULTURE. 
(b) Frame-bent trestles are made of both round and sawed tim- 
bers. If the former material has to be brought from a considerable 
distance, it is advisable to use the latter, since it is easier to fit and 
is more durable. On the longer main-line logging roads, most of the 
frame trestles are built of sawed timber, the trestles on the spurs 
being usually built of round timbers. Not infrequently, however, 
the stringers used in connection with the construction of the trestles 
on these latter roads consist of sawed timber. Where suitable pole 
timber is available, a rough-timber trestle can be constructed more 
cheaply than one with a sawed frame. 
The general appearance of a frame trestle is much the same as 
that of a pile trestle. The bents, which are spaced 13 to 16 feet apart, 
consist of four legs made of round timbers 14 inches and up in diame- 
ter or 10 by 10 inch or larger square timbers. Each bent rests upon 
a sill, which may be either a log or a 10 by 12 inch sawed timber. 
Round or sawed timbers are used for caps and stringers. 
In computing the cost of frame trestles, the lumber used is com- 
monly included at $12 per thousand feet. A convenient way of 
figuring the cost of any trestle is at so much per 1,000 feet of the 
material contained in it. This cost includes lumber, bolts, and other 
supplies, and the labor of building the foundations and framing the 
trestle. The cost of several representative standard-gauge frame 
trestles recently constructed on logging railroads in this region is 
given in Table 31. 
Table 31. — Cost of frame trestles. 
Length, 
Maxi- 
mum 
Feet 
Total 
Cost per 
Cost per 
linear 
feet. 
feet. 
height, 
feet. 
b.m. 
cost. 
M feet. 
620 
52 
105,000 
$2, 800 
$26. 66 
$4.52 
652 
28 
60,000 
1,565 
26.08 
2.40 
762 
8 
68,000 
1,704 
25.06 
2.23 
202 
32 
28, 000 
743 
26.54 
3.68 
140 
34 
19,000 
487 
25.63 
3.34 
238 
31 
31,000 
724 
23.35 
3.04 
272 
41 
45, 000 
1,030 
22.89 
3.77 
144 
54 
30, 000 
713 
23.76 
4.95 
TRACK MATERIALS. 
The following discussion has to do with standard-gauge material, 
Crossties. — Both sawed and hewn ties are used in constructing log- 
ging railroads. Where the logging operator is also engaged in the 
manufacture of lumber, and the sawmill is close to the logging camp, 
most of the ties used are sawed. Independent loggers, as a rule, use 
hewn ties exclusively. 
Sawed ties vary in size. The usual size on standard-gauge roads 
in the region is 7 by 9 inches by 8 feet. Ties 7 by 8 inches by 8 feet 
