Vermont phÅ“nix. [volume] (Brattleboro, Vt.) 1834-1955, 1873-01-31
PUEBLO, COL, Jan. 18th, 1873.

portunity to reply. Now that begin, l
find myself greatly at loss to know Just
what particulars you desire. In the early
agitation of the narrow-gauge movement,
there was much printed Information on the
subject that might have been valuable to
you-theoretical and practical. suppose
you are already supplied with this. The
best articles on the subject were published
by Mr.. II. f. Fairlee, an English engineer
of repute, aud by c. Il. Spooner, chief en-
gineer and manager of tho Festiniog rail-
way, living ut Port Madoc, Wales. re-
greet that have not now copies of these
works to forward you ; but am sure they
would gladly send them on application.
Our own experience with the three feet
gauge has been most satisfactory. We have
now in operation 155 miles of line, much
Of which we have operated for more than
year past. 1t has very little that is novel
or peculiar in its construction, beyond a
simple adaptation of ordinary principles of
railway construction to the requirements
Of a lesser gauge. The project covers an
immense amount of territory. The main
line skirts tue base OF the Rocky noun
tains from Denver 10 the northern bound
airy Of Mexico-S00 miles-where il unites
with the national railway system Of Mexi-
co, under the same management and to be
of the same gauge. On either hand are the
mountain ranges, prolific OF every miner
al, only accessible through narrow, tortu-
Gus, rocky canons, to build railway Of
ordinary gauge through which would, on
account of enormous cost, be impractical
BILE. This was the most important reason
for our choice of gauge-the fact that our
greatest traffic must come from the miner
al districts of the mountains; and that on
ly by narrow-gsuge system could we
penetrate these mountains and obtain it.
On our present main line from Denver to
Pueblo-l20 miles-the maximum gradient
used is rs feet per mile, with maximum
curvature Of degrees (955. feet radius.)
The gradients are long and curves frequent.
On our branch line from Pueblo to the coal
fields, up the Arkansas river, IS miles, we
use frequently curves of 20 degrees (radi-
us 2S7 feeU and, in one instance, giadi-
ent of ITO feet per mile. During the con-
struction of this branch we used for tenn
porary purposes, gradients of 200 feet, and,
in some cases, curves of 80 degrees (radius
l0l feet) reversed on others OF the same ra-
dius. 1 have not yet learned that the gra-
dent is dependent upon, or affected by the
gauge. Tle amount of traction that will
suffice for load of 100 tons on the narrow
gauge, will haul the same load on the
feet 81 inch gauge. or on the feet gauge, If
we disregard the resistance due to axle or
nange friction, and the advantages of con-
centration of power, the latter being still a
mooted question among engineers. The
grade which would be profitable TO operate
if your line were built on standard gauge,
will be as protitably operated ON the mar
row-gauge. The economy of the latter is
entirely apart from this. The question of
curvature is harder TO decide. Our main
line curves are less than those of many
eastern roads of broad gauge. On the
branch we operate daily curves of 20 de-
grees; but these are operated at slow speeds
of not over Is miles per hour. The pre-
else amount of difference in resistance due
to curves between the two gauges has been
formulated by some one, but no formula
can be made to cover the ground. My i'm
preston is, however, from close observa-
ton during the past year, that curves of
one-half shorter radius may be used upon
the feet gauge than upon the feet 81 inch,
with even less resistance, and with the
same safety.
The Central Colorado Railway Co. have
line extending from Denver into the
mountains, with three feet gauge, 2S miles
grees (radius 900 feet, reversed, and often
on gradients of $50 to 2ll feet per mile.
They use, however, truck having loose
wheel on each axle, making one wheel in
dependent of the other, and dispensing
with sliding friction to great extent. Slch
curves, by this means, seem to offer scarce
ly more resistance than ordinary curves of
3 to degrees on broad gauge roads. /
should advise the adoption of the loose
wheel on lines having a sharper curvature
than 10 degrees. They seem to give per-
feet satisfaction. The difference In cost of
construction Of the Two systems, is one of
It's greatest merits The estimates for
building our main line, from Denver TO Pue-
bio, on the feet s! inch gauge, were So, 900
per mile. Using the same location, grad
tents and curves, the actual cost of our
present line, with equipment, rolling stock,
machine shops, stations, warehouses, &C.,
was $4,000 per mile. We use 2G4O ties
per mile; weight of rail, 80 lbs. per yard
but would advise SO lbs, where transport
tation from works is not too great, or whore
the traffic is likely 10 be immediately heavy.
Passenger engines, weight l2l tons, 10
tons Of which are on the four drivers-tbe
drivers being 30 inches in diameter. These
answer very well for train Of three or
four cars, on our long heavy grades, with
an average speed not exceeding 20 miles
per hour. On easy grades an average speed
of 20 TO % miles per hour could be main
tanned with them with gross load not ex-
ceeding 30 tons. I should, however, adj
wise an engine OF slightly different CON-
struction, which with perfect ease and safe
ty, would ensure speed of 25 TO 30 miles
per hour, or faster If necessary, and would
pull a train to accommodate $50 TO 200 pas
sengers. Engines for freight are of the
same general pattern as passenger engines,
but have drivers 36 inches in diameter, Is
tons weight, available for traction 81 tons
on leading truck. We find II very desira-
BILE to obtain engines of greater weight and
capacity without increasing materially the
weight on each driving wheel, and have
ordered Fairlie double boyle engine for
trial. Our heavy gradients renders this
necessary. BY the use Of such engines,
having one third greater capacity, we hope
to reduce our operating expenses 10 per
cent, and perhaps more, Passenger cars
presu mo you have photographs and de-