330 LOGGING 
the machine is run out to the end of the road, the rail fastenings 
removed, and the rails pulled, by a power driven cable, over 
rollers to the bunks on the car. The crossties are then picked 
up and placed upon the endless chain on the cantilever arm which 
carries them to the rear of the machine where they are stacked 
upon the 2- by 4-inch timbers on top of the sills. As loading 
progresses additional strips are placed along the chains until 
the front end of the machine is reached. In track laying the cross- 
ties are rolled down upon the endless chain and carried to the 
end of the cantilever arm where they are placed in position by 
the crew. The rails are rolled from the bunks upon rollers 
along the side of the car and then pushed forward where they 
are picked up by means of rail tongs and carried forward and 
dropped upon the crossties. When the rails are in position, the 
rail fastenings are adjusted, and bridles are placed on the rails at 
intervals of 7 or 8 feet to hold them upright and in position until 
the track layer and locomotive have passed. Spiking is done 
behind the locomotive since more speed can be made by this 
method. This machine can be operated with a crew of eight 
men but a crew of from fourteen to sixteen is more efficient. 
The back-spiking crew is followed by the surfacing gang which 
levels up the roadbed with ballast, digs or opens drainage ditches 
alongside of the track, adjusts the gauge, raises the outer rails on 
curves, and performs any work necessary to put the road in a 
condition for operation. On main lines a large amount of sur- 
facing may be done, but on spurs it is limited. 
Roads which have sharp curves must have the gauge widened 
to reduce the frictional resistance of the wheels against the rails. 
It is customary to widen the gauge at least iV"iiich for each 2| 
degrees of curvature in excess of 5 degrees. For example, the 
gauge would be increased |-inch for a 20-clegree curve. The 
extra width allowed is dependent chiefly on the width of the car 
wheel treads. 
The centrifugal force of a train under speed tends to force the 
wheels against the outer rail. This tendency increases with 
speed and is greater on a sharp curve than on an easy one. It 
is overcome by elevating the outer rail and lowering the inner 
one and also by coning the tread of the wheels. The diagram 
(Fig. Ill) shows the customary elevation for standard-gauge 
track on curves up to 40 degrees and for speeds up to 30 miles 
