The Water Supply of the El Paso and Southwestern Railway from Carrizozo to Santa Rosa, N. Mex. | Page 4

temperature. This coating endured a 2,000-mile shipment
successfully. Each piece was carefully inspected along the trench, and
any break in the coating was thoroughly painted with hot asphalt.
Enough of the latter came in barrels, with the pipe, from the factory.
The first 37 miles of this pipe has been in service for two years. Recent
inspections show the coating to be in excellent condition and the steel
underneath to be bright and clean. In some cases, where the initial
pressure and leaking between the staves of the dry pipe were great, the
escaping air and water lifted the coating into bubbles. At some points
where this lifting was great enough to rupture the asphalt, and the soil
is heavily charged with alkali, some corrosion has begun.
The integrity and impermeability of this asphalt coat are quite as vital
as constant saturation. This coating protects the entire pipe from
exterior contact with destructive agencies. With such effective exterior
protection, a constantly full pipe is not so imperative. In the exterior
protection of the wood, this coated pipe has quite an advantage over
continuous stave pipe.

Each piece of pipe goes directly from the winder to the asphalt rolls,
then to an adjacent saw-dust table, then back to the rolls, then to the
table again, and then to the dry finishing rolls at the opposite end of the
table. The coating thus consists of two layers of asphalt and two of
saw-dust. When the pipe leaves the finishing rolls, the coat is hard and
smooth and about 1 3/16 in. thick. This describes the coating as done at
Bay City, Mich.
At Elmira, N.Y., one application of asphalt and saw-dust only, without
a finishing dry roll, completed the work; but the band was run through
a bath of hot asphalt as it was wound, thus coating its underside also.
This initial treatment of the band on the Wykoff pipe is necessary
because the exterior of the stave is neither planed nor turned to a circle.
The exterior of the pipe forms a polygon, and the band is in perfect
contact only at the angles. The theory in regard to the Michigan pipe is
that the perfect contact of the band and the wood on the true exterior
circle excludes air from the under surface of the metal, and prevents
corrosion. Experience appears to justify this theory.
_Cast-iron Pipe_.--Beginning at the first pumping plant at Coyote, at
Mile 156, and running up to Mile 166, and again commencing at the
Luna pumps, at Mile 171, and extending up to Mile 179, the minimum
pressure on those portions of the pump main is more than the 130 lb.
per sq. in. allowed for wood pipe, and the final estimated maximum
pressures run up to 310 lb.
The selection of iron pipe for these pressures was, first, as between
steel and cast-iron; and, second, as between the lead joint of the
standard bell and spigot pipe and the machined iron joint of the
universal joint pipe. Again, the choice was as between lead and leadite
for the bell and spigot pipe.
Cast iron was selected because of the certainty of its long life, and the
bell and spigot pipe was selected on the basis of comparative costs for
pipe laid. The standard lead joint was chosen on the result of tests. This
cast-iron pumping main has a diameter of 12 in. throughout.
_Pipe Weights._--Makers of standard bell and spigot pipe urged the

usual heavy weights selected for municipal service and heavy
water-hammer. Three pressures, viz., 217, 260, and 304 lb., were used
for the division of pipe weights, on which the standard pipe-makers
specified shell thicknesses of 0.82, 0.89, and 0.97 in. Eliminating
water-hammer and adopting a working stress of 2,400 lb., the
thicknesses are reduced to 0.54, 0.65, and 0.76 in. To make the latter
conform to the specifications of the New England Water-Works
Association, the pipe was cast to 0.57, 0.65, and 0.77 in. The reduction
in cost amounts to $52,811.
By the provision of air-cushions, hereafter described, the writer's
anticipation of no water-hammer on the pumping main has been fully
realized.
The pipe was manufactured and inspected under the above-mentioned
specifications.
Pipe Joints.--There was a question about the reliability of the lead joint
at 300 lb. The writer had a section of 12-in. pipe, with standard joints
containing 22 lb. of lead, laid and tested to 500 lb. without sign of
failure or leakage. The joints were caulked down 3/16 in. below the
face of the bell. Of 8,700 joints thus made in the field, not one has
blown out or failed. A few weeped slightly on top, and they were made
permanently tight by additional caulking. The present maximum
pressure is 278 lb. These joints are the standard joints specified by the