PORTLAND CEMENT CONCRETE PAVEMENTS. 23 
From a purely economical standpoint the choice of means for haul- 
ing the materials would probably be made about as follows : 
First. Where the maximum haul does not exceed 3 miles and the 
amount of concrete to be laid does not exceed about 5,000 cubic yards, 
team haul would probably be economical. 
Second. If the amount of concrete to be laid exceeds about 5,000 
cubic yards, or if the maximum haul exceeds about 3 miles, and the 
materials are hauled in from the same direction, an industrial rail- 
way, tractors, or motor trucks may be economically used. 
Third. Where the materials are hauled in from each end of the 
road, or where it is desired to operate more than one mixer at the 
same time, the industrial railway is usually more practical and 
economical. 
Where the sand and coarse aggregate are shipped in by rail, the 
work of unloading the railroad cars and loading the wagons or cars 
in which the materials are to be hauled out to the work can usually 
be most economically done by means of machinery especially adapted 
to this kind of work. In order to avoid paying demurrage, and to 
have the materials on hand when they are needed, it is nearly always 
necessary to handle a considerable part of the materials the second 
time. Hence it may be desirable to have two sets of unloading and 
loading machinery in cases where the stock piles and bins are located 
out on the work instead of at the siding where the materials are 
delivered. 
The kind of unloading and loading device to employ depends to 
a very great extent on the quantities of materials to be handled and 
the other conditions to be met. If the stock piles and bins are ad- 
jacent to the siding where the materials are delivered, and a consid- 
erable quantity of work is to be done, a locomotive crane may fre- 
quently be used to advantage, while, if the stock piles and bins are 
out on the work, it may be economical to handle the material at the 
siding with scrapers or similar devices and install an elevating device 
at the bins where the materials are stored. In other cases the extent 
of the work may not be sufficient to warrant any machinery whatever 
for handling the materials, in which event the handling may be rather 
expensive. 
CAPITAL REQUIRED. 
The amount of capital required to carry on concrete road construc- 
tion successfully depends almost wholly on the size of the project and 
the circumstances under which the work is to be done. Where a con- 
siderable quantity of work is to be done in the same community it 
may be possible to keep a very elaborate equipment busy, even though 
the individual projects are comparatively small. On the other hand, 
it may be poor economy to provide more than the smallest practicable 
