ENGINEERING REPORTS. (J 7 
It will be seen on reference to the table of total quantities of 
excavation, that a little less than one quarter of the whole 
amount of earth-work is of solid and loose rock. This, however, 
should not be looked upon as a bad feature, especially in a 
country where the rains are sudden and heavy, as the cost of 
repairs of a road built upon a rock base, would necessarily be 
less than one built upon an earth base. 
Superstructure. 
For the superstructure I have estimated a T rail of 70 lbs. to 
the yard. From Paso de la Puerta to Xochiapa, there is the 
greatest abundance of encina (a species of live-oak), suitable 
for cross-ties. Sub-sills have not been estimated for, for the 
reason that the nature of the road-bed will not require them ; 
besides, they are falling into general disuse on account of en- 
hancing the cost of repairs. 
One-mile Estimate for T Rail. 
T rail 70 lbs. to the yard, 123-2 tons, at $40,* $4928-00 
2310 cedar, encina, or caoba cross-ties, 7 to the length of 
each rail of 18 feet, at 25 cts,, 577-50 
660 cast-iron chairs, 20 lbs. each, at 75 cts., 495*00 
Switches, frogs, &c, per mile, 30*00 
5290 lbs. rail-spikes, at 6 cts., 317-40 
Laying track, distributing timber, iron spikes, chairs, frogs, &c. 750'00 
Contingencies, 40-00 
Total cost of one mile of track, . . .$7137-90 
The prices of the rails, chairs, spikes, &c, include that of 
freight to the Isthmus in the above estimate. 
Equipment Estimate for opening the Road from the Rio Jaltepec to Ventosa. 
4 Locomotives for passengers, 21 tons,.. . 
.. .at 
$9,500 
= $38,000 
10,500 
= 63,000 
2,500 
= 25,000 
1,400 
= 5,600 
1,400 
= 8,400 
800 
= 80,000 
30 Platform " 
650 
= 19,500 
25 Gravel " 
425 
= 10,625 
10 Hand " 
150 
= 1,500 
Total, including freight to the Isthmus, . 
$251,625 
* Iron is admitted on the Isthmus free of duty. 
