322 LOGGING 
in diameter across the right-of-way on either side of the stream 
or depression and covering them with slabs spht from 12- to 18- 
inch timbers^ Brush is often piled on top of the slabs to prevent 
the dirt from falling through, and the grade is then built over the 
culvert. 
When the span is short and the grade is high enough above the 
stream to permit it, several poles or crossties may be laid across 
the gap parallel to the roadbed, and the crossties supporting 
the rails placed on top of them. 
Box culverts made of plank are seldom used because of the 
greater cost for material. Round galvanized iron culverts are 
now used on some main lines. 
Cattle Guards. — Log roads that pass over private lands or 
cross public highways use cattle guards to prevent stock from 
passing down the right-of-way. The usual type is an open pit 
3 or 4 feet deep, 5^ feet long and 3 or 4 feet wide, which is in- 
closed with a frame of 12- by 12-inch timbers. A division fence 
extends from the guard to the highway fence. 
TRACK SUPPLIES 
Crossties. — The size of crossties used depends on the gauge 
of the road. They may be sawed or hewed. Narrow-gauge ties 
are made 6 or 7 feet long and standard-gauge ones are 8 feet. 
Squared ties are 6 by 8 inches in size and pole ties, for a narrow 
gauge, have a 3- to 5-inch face, and for a standard-gauge a 6-inch 
face. 
Ties usually are cut on the operation and are made both from 
hardwoods and softwoods. Hewed pole ties made from second- 
growth pine are seldom as satisfactory as squared ones because 
they break readily and cause frequent derailments. An expert 
tie hacker will hew thirty-five or forty standard ties per day, an 
average man twenty-five or thirty. Some operators who own 
sawmills and cut crossties for the market use the rejects on their 
logging operation. 
New ties are placed at 24-inch intervals, center to center, on 
main lines and spurs. On the latter they wear out before they 
decay because of the frequent pulling and driving of spikes. On 
tangents only every other tie may be spiked which lengthens its 
1 See Fig. 106. ' 
