ENGINEERING EEPOETS. 
Estimated Cost of Construction. 
61 
In the event of the final location of the road west of the Coat- 
zacoalcos River, it may be thought advisable to construct that 
portion from the Jaltepec to Ventosa previous to that from 
Mina-titlan to the Jaltepec. These portions, therefore, have 
been estimated separately. 
The estimate is made for a single track, of six feet gage, 
with the requisite side-tracks and turn-outs, and on a road-bed 
of twenty-two feet wide in excavation, and sixteen feet in em- 
bankment, with slopes for cuttings of one and a half to one in 
earth, and one-fourth to one in rock ; and for filling one and a 
half to one in earth, one to one in rock. These, however, on the 
construction of the road, will be subject to modification where- 
ever the nature of the material requires it. 
The estimated quality of the material is only approximate, 
but will generally be found near the truth. 
The masonry for culverts are supposed to be of good, substan- 
tial, hammered rubble arches, laid dry. The bridge abutments 
and piers, with hammer-dressed beds and joints, also laid dry, 
and the bridge superstructure of wood. 
I should not however recommend, in every case, the building 
of the bridge masonry before getting the road into operation — 
for the transportation by teams of the stone and material for 
these works, where the haul is considerable, would involve heavy 
expense and delay, owing to the entire absence of roads and the 
difficulty of getting to quarries. It would perhaps be better to 
substitute temporary trestle-work over the site of the bridges, 
as an abundance of timber is generally close at hand. In some 
places it may be expedient to substitute the same for those em- 
bankments which require a long haul, as otherwise too much 
time would be consumed in the building. For the same reason, 
and to get the road into operation as soon as possible, it may 
be advisable to build it on piles in some places north of the Jalte- 
pec. In this way the road could be put in operation much 
sooner and at a less expense ; for the saving of time and the cost 
of hauling material by teams would more than compensate for 
the expense of the trestles. The stone for the bridge masonry, 
