70 ANNUAL REPORT 
finish with Portland cement concrete of the proportions 1-3-6. The 
excavation cost 50 cents per cubic yard, natural cement concrete $4.00 per 
cubic yard and Portland cement concrete $6.25 per cubic yard, making 
the cost of the maximum section as shown in the accompanying figure to 
be $23.65 per lineal foot of wall. 
The wall upon the west side of the right of way is designed with 
a base width of four-tenths its height, consequently is considerably 
cheaper ; the cost of such a wall being $20.53 against the cost of the first — 
or a saving of 15 per cent. on the basis of the lighter wall, the latter being 
perfectly safe practice. 
. Portland 
Po 7 ~Gement 
oe: ae “4 Goncrefe ° 
Ca ‘ 
PANS Co 
Natural Cement Concrete. 9 
Fig. 18.—Section of Retaining Wall C. R. I. and P. 
R. R. Showing Maximum Section. 
The contract specifies that the cement shall be of first class quality, 
acceptable to the railway company. ‘The sand shall be what is known as 
torpedo sand. ‘The stone shall be good crushed limestone. The wall was 
2 eg) aaa 
