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once in a record for rapid construction, when 93 miles of railroad from
Medicine Hat was built in 23 working days of June, 1883. This work,
which included grading, bridges, culverts, and track-laying, but not
very much ballasting, really made a marvelous record, considering
the fact that all the supplies had to pass through Winnipeg and then
be carried some 600 miles over a new, single-track railroad.

In those days no one ever thought that that railroad would ever
be a financial success; it was considered merely as a political necessity,
as the Dominion Government, at the time of the Confederation in
1867, had assumed the obligation of making physical connections
between the separated provinces. Even the late Commodore Vanderbilt
had so little confidence in it that he got rid of his holdings. , (

As a matter of fact, in those days, British Columbia was closer,
commercially, to the United States than it was to the rest of the
Dominion; and, even in 1885, the speaker found that Ontario or
Quebec banknotes were not welcomed in British Columbia and were
accepted only at a discount, while United States notes were accepted
at par. This was partly due to the fact that in those days the face
value of a Canadian banknote was not guaranteed by the Government
as it is now. At present, however, the Canadian banking system is
superior in many respects to that in the United States where a
national bank in a small town has only the credit of its small capital
back of it, whereas the smallest branch of some dozen strong Canadian
banks has its powerful system behind it. Very few Canadian towns
are not amply provided with such branches.

One reason for haste in those days was to get some return on the
money as soon as possible, and an even more important reason was
the fear that, if the road was not quickly completed, a turn of the
political wheel might prevent it from being finished for many years.

In addition to the commercial reasons for haste in constructing
the Rogers Pass Tunnel, the fear of snow slides may have been
another incentive — the author has stated that the snowfall there is
from 30 to 50 ft. a year. The speaker assisted in the design of the



DISCUSSION ON TUNNEL CONSTRUCTION METHODS 481

first snowsheds on this road. These were to be constructed in cuts on Mr.
the hillsides in such a way that the snow slides or avalanches would '''"^o"-
never strike directly on the roof of the shed, but merely shoot
or slide over it. Some of these designs were modified by others, so
that the roofs projected up too far, with disastrous results in every
case. Trees adjacent to a snow slide would often be cut off as if by
a knife about 20 ft. above the ground, or at the surface of the standing
snow, by the force of the wind generated by the falling avalanche.
Nothing can be built to stop those giant snow slides after they have
fallen from 3 000 to 5 000 ft. The snow and ice piled up in winter
many feet, and even after the intense heat of August a depth of some
30 ft. or more would be left.

Would it not be appropriate for the author to insert a brief sketch
of the life of Major Rogers, one of the most unique characters of a
past age of remarkable engineers? He saved the Canadian Pacific
Railway from following the Columbia River some 200 miles around —
north and then south — by discovering the Rogers Pass which led due
west, crossing the Columbia River twice.

The exceedingly favorable geological conditions encountered in this
tunnel were not often found in the earlier tunnels in the Selkirks,
one of which — a mud tunnel — was nearly completed when it was found
that the two headings did not meet by 18 in. This was first blamed on
the engineer, but after the lining had been ripped out and replaced,
the tunnel at once collapsed. It was re-opened a third time, and again
collapsed, after which it was abandoned, and the railway was run
around the bluff on a 23° curve. It was operated on this curve for
more than 20 years, and then a new tunnel was built much farther
from the face of the bluff, where firmer ground was encountered.

In those days some of the grades were as high as 4J%, and nego-
tiating them gave the engines so much trouble that safety switches
were generally placed at the foot of the grade, so that if the train ran
away it would have to take the switch, which had such a sharp grade
uphill that the momentum of the train would rapidly be reduced.

The plan and profile. Fig. 1, shows how the original location wound
around the hillsides in order to avoid more excessive grades, and per-
mitting as rapid and cheap construction as possible. The profile also
shows why vertical shafts could not be considered, as the hills stand
as high as 5 000 ft. above the tunnel.

Francis Lee Stuart,* M. Am. Soc. C. E. — The speaker has read Mr.
this paper with interest, as the rate of progress was strikingly rapid. ^^^ '
As far as the speaker knows, a pioneer tunnel, similar to that used
at Rogers Pass, has never been built in the East, although this method
is in constant use in coal and iron mines. Usually, the tunnels in

• New York City.



483 DISCUSSION ox TUXXEL COXSTRUCTIOX METHODS

Mr. the East have not been so long, have had less cover, and construction
■ progress has been expedited by shafts. The speaker has found it very
difficult to compare the progress in tunnels — every one seems to
have different conditions which affect the rate of building — in fact,
even parts of the same tunnel are not comparable. In groping after
a greater speed, a number of new methods have been tried.

In the Stuart Tunnel, one of the most recent built under the
speaker's direction, at the Magnolia Cut-Off, on the Baltimore and
Ohio Railroad, the tunnel section used was large, being 31 ft. in the
clear horizontally, with side-walls plumb to 11 ft. above sub-grade, and
a semicircular arch with 15^ ft. radius, giving a clear height of 22 ft.
11^ in. at the center of each track.

To expedite matters, the contractor, H. S. Kerbaugh, Incorporated,
put in a Marion 28 (f-yd.), dipper, air-operated shovel with which he
widened the heading, which originally had an area of about 120 sq. ft.,
and took the bench to an elevation 6 ft. below that of the wall-plate,
leaving 11 ft. in bench instead of the usual 17 ft. It effected a very
considerable saving in time and expense, as it was possible to widen
and place the steel segment at a rate of from 60 to 70 lin. ft. of arch
section per week, as compared approximately with 45 ft. by hand, and
to enable the remainder of the bench to be drilled without cat-holes.
The speaker thinks that matters were about even, as to cost, and, with
a little better roof, it should have been cheaper than the old method.

In a further effort to increase the rate of progress in the tunnel,
it was decided to use Blaw steel segments to support the roof, in place of
the usual timber segments. These consisted of two 7-in., 14|-lb. chan-
nels, riveted together with two |-in. rivets, 2^ in. long, with 6|-in. fillers
between, at intervals of about 3i ft. These segments were divided into
three parts ; the central portion was 18 ft. 3| in. long, curved to a radius
of 17 ft. 6 in.; the end portions were 11 ft. 31 in. long, 5 ft. 0| in.
being curved to a radius of 17 ft. 6 in., and the remainder being a
tangent to connect with a flanged foot resting on the wall-plate.

The three sections were connected with 9 by |-in. plates, 1 ft. 9 in.
long, and with |-in. fillers. They were used in 2 015 ft. of this tunnel,
or for 60% of its length, and, for the most part, were 5 ft. from
center to center; otherwise they were 7 ft. 6 in. from center to center,
depending on the character of the roof. All were tied together longi-
tudinally with |-in. tie-rods 7 ft. from center to center. The lagging
was placed directly on these segments, and was fastened through -f'^-m-
holes in the flanges. The sections were assembled in the tunnel and
raised to position.

The use of these steel segments enabled the driving to be done more
rapidly, as the cross-sections decreased an average of about 2 cu. yd.
per lin. ft., and, as the segments came entirely within the section of



DISCUSSION ON TUNNEL CONSTEUCTION METHODS 483

the concrete liniBg, there was an additional saving of practically Mr.
2 cu. yd. of concrete per cu. ft. "^'^ '

The speaker's conclusion was that speed was made by the use of
these forms — whether or not they were cheaper could not be determined.

J. Y. Davies,* M. Am. Soc. C. E. — The only thing the speaker has Mr.
against this paper is its great brevity. The author has described a
piece of tunnel work which has two peculiar and important features:
first, the rapidity of the driving; and, second, the use of a "pioneer"
heading.

To have done the amount of driving in the headings which was
accomplished on this work for one month, is one thing, but to continue
that work at the rates actually obtained, an average speed of 24 ft.
a day for 7 days a week in one heading, and for 20 ft. a day for 7 days
a week in the other heading, is really a wonderfully fine piece of work.

It indicates very clearly an extremely perfect organization in every
department, and the speaker presumes that it is to be understood,,
from Mr. Lauchli's discussion, that that progress was in part due to
the fact that the conditions, as they developed in the driving, and the
conduct of the work, were almost perfect. There were no high tem-
peratures; there was no entrance of hot water, as is so common in
mountain ranges, and, in fact, very little water at all.

The comparison of that work with the best that has been obtained
in the United States and elsewhere is interesting. The only tunnel
in America (for which the speaker has figures) which exceeds the
Rogers Pass monthly record (and that probably was only for an excep-
tional month), was the Red Rock Tunnel, built in 1901, in which a
speed of 1 OGl ft. for the month was attained; but that was in soft rock,
where the boring was done with hand-augers.

The other tunnel to which the speaker refers is the Elizabeth
Tunnel, on the Los Angeles Aqueduct, where Leyner drills were used
in gneiss rock, and there the maximum progress was 641 ft. a month.

In the Roosevelt Tunnel, in Colorado, in granite, the speed was
only 435 ft. a month. There, also, Leyner drills were used.

In an extensive undertaking of tunnel construction which the
speaker's firm carried out in Mexico, a few years ago, heading progress
was obtained, in hard limestone rock, as high as 536 ft. a month, using
Leyner drills. The use of these drills has made a very marked increase
in the rapidity of tunnel work.

Now, take the foreign tunnels: in the Simplon, in rock of a char-
acter probably very similar to this — hard, gneiss rock — a speed of 685
ft. was attained; in the Loetschberg Tunnel a rate was attained, in
the north heading, in a hard limestone, of 1 013 ft., whereas in the
south tunnel the rate was only 545 ft. ; so that this Rogers Pass Tunnel
work stands out pre-eminently as the most rapid that has been accom-

• New York City.



484 DISCUSSION OK TUNKEL CONSTRUCTION METHODS

Mr. plished in America up to the present day, and is almost equal to any-
^^"^^' thing that has been done elsewhere.

There are various questions which arise from reading this paper,
regarding which it would be of considerable value to the membership
to have further information, and the speaker hopes that the author
may feel willing to go outside of the scope of the paper as presented
and give some further information which would add materially to
its value.

The particular point of great interest is the value of the "pioneer"
tunnel. The author refers to it briefly in the paper as an economical
question, and it would be of much value if he could add something in
the nature of a balance sheet, having on one side the advantages
obtained from the construction of the additional heading, and on the
other side the increased cost of driving two heading excavations, as
was actually done.

The excuse and reason for a "pioneer" tunnel are unquestionably
to increase the speed of construction of the main tunnel, in which
there is a large bench to take out, as is involved in the enlargement
of such a structure as this double-track railroad tunnel, where the
value of the time element, in removing the bench and enlarging to
full size, is the main factor involved on the one side of the bal-
ance sheet.

There is no doubt that speed can be attained by the driving of a
"pioneer" tunnel, and undoubtedly in this case, as the author states,
there was warrant for its construction.

Several of those discussing the paper have made remarks as to
how the "pioneer" tunnel originated, but it seems to the speaker that
any one who has studied the construction of the Simplon Tunnel, as
described very fully by Sir Francis Fox,* would be satisfied that the
use of the gallery in that work gave the idea from which the "pioneer"
tunnel was adopted in this work.

It was used in that work unquestionably for the purpose of ventila-
tion, for transportation and drainage, and to expedite the work.

On the other hand, there was another guiding reason in the Simplon
for the adoption of the gallery, as the plans for that tunnel contem-
plated two single-track railroad tunnels, approximately 55 ft. apart, to
be built for east- and west-bound traffic, respectively, and the "pioneer"
tunnel was located as the side-wall heading for the second tunnel. It
is now being enlarged, or has been in the last few years, to make the
second tunnel; but it was located in that position unquestionably for
the same purposes as the "pioneer" heading in the Eogers Pass Tunnel
was driven, having in mind, undoubtedly, later enlargement for the
second tunnel.

* "The Simplon Tunnel", Minutes of ProccecUnr/s, Inst. C. E., Vol. CLXVIII
(1906-07), p. 61.



DISCUSSION ON TUNNEL CONSTRUCTION METHODS 485

In the Simplon Tunnel the gallery was lined with the permanent Mr.
side-wall construction at the same time. avies.

In the Rogers Pass Tunnel, as described, there were none of the
difficulties which were encountered in the Simplon Tunnel and made
the use of a '"pioneer" tunnel there so vital to the success of the
undertaking.

In the Simplon Tunnel, the "pioneer" tunnel (or gallery, as it was
called) was carried right through from end to end, and the gallery was
enlarged so as to make a passing siding for trains in the center of
the tunnel.

The speaker will be quite interested to obtain from the author at
a later date some information as to what pressure he used in the ven-
tilating system, with the Connersville blowers, under the conditions
developed in driving this long-distance tunnel. The difference between
any short tunnel and one of this length, with no intermediate shafts
and no inter^nediate access, is one of the features of this undertaking
which is of very great importance. The ventilation question becomes
of the utmost importance, and the pressures at which the ventilating
apparatus was operated to produce the forced draft for which the Con-
nersville blowers were used, is of considerable interest.

Another matter on which the speaker thinks some further informa-
tion would be of considerable benefit to the Society is a statement as
to the detailed plan of the bonus system which was adopted for the
acceleration of labor, as only a vague reference is made to the subject
in the paper. The speaker would also be glad to have a schedule of the
rates of wages paid to the men on that work.

S. A. Knowles,* Esq. — In reference to the speed at the Kogers _ Mr.
Pass Tunnel, Mr. Mcllwee, the original contractor, who was responsible °°^^ ^^'
for the methods and organization, had had similar contracts at the
Roosevelt Drainage Tunnel, in Cripple Creek, the Laramie-Poudre
Tunnel, and several others, in which he had been successful in main-
taining a high average footage. The organization which was assigned
at the Rogers Pass Tunnel had been with him on his previous under-
takings, and thus their combined experience enabled him to obtain
such desirable results.

An essential factor in obtaining a high and uniform footage was
the ventilation. The speaker had an opportunity at one time to test
the ventilating system, which comprised 12 000 ft. of practically straight
18-in. steel pipe of No. 16 gauge. A No. 7 Root blower, running at
100 rev. per min., gave a displacement of 6 500 cu. ft., and the indi-
cated horse-power required for either blowing in or exhausting this
quantity of air per minute was about 20.

* Sault Ste. Marie, Mich.



4:86 Discussiox ox tuxxel coxsteuctiox methods

Mr. E. E. Dougherty,'^ M. Am. Soc. C. E. — The method used in driving:

oug er y. ^^^.^ tunnel, which distinguishes it from the methods utilized in similar
instances, involves primarily the so-called "pioneer tunnel." The
arrangement is one which is somewhat new in tunnel driving, but
the fact that the necessary results were secured by the contractors
and the railroad company speaks for its success.

In sending out invitations to the contractors, the Chief Engineer
of the Canadian Pacific Kailway called attention to the fact that
time was a very considerable factor, to such an extent as to be worth
about $750 per day, and those who have had anything to do with rail-
road operation can very readily appreciate the significance of the time
element. It is altogether possible that the tunnel might have been
constructed by the so-called American methods, at a lesser cost, but
the fact that all American records were broken, and the maximum
results obtained by European methods approximated, would justify
the means used.

Furthermore, from the standpoint of economy, reference might
be made to an article by Mr. Sullivan, Chief Engineer of the Canadian
Pacific, which appeared in one of the engineering periodicals, in
which he states that the actual cost of construction was approximately
$5.00 per cu. yd. of the main heading, from portal to portal, which
included the cost of the pioneer tunnel, 5 miles of railroad to the
site of the work, overhead charges, and all other costs involved. Fur-
thermore, other bids secured by the railroad company ranged from
$8.00 to $11.25 per cu. yd., although an estimate of $5.50 per cu. yd.
was given by one contractor, based on the American method, but
calling for a much greater length of time than was actually consumed.
As a basis for comparison in the matter of progress, the maximum
rate per month per heading attained at the Rogers Pass Tunnel was
946 lin. ft.; this approximates very closely the maximum rate of 1013
lin. ft. per month attained in the construction of the Loetschberg
Tunnel, in Switzerland.

In making a comparison of the methods used in the construction
of other long tunnels, the only work which appears to have been on
a similar basis is that involving the Simplon Tunnel in the Alps
between Italy and France. The Simplon Tunnel was constructed for
a single track, with a smaller atixiliary tunnel which was designed
to become a part of a future parallel single-track tunnel, the prime
purpose of the auxiliary tunnel having been to permit adequate
drainage, as well as to facilitate the handling of material, etc. With-
out this auxiliary tunnel, it would have been almost impossible, in
all probability, to construct certain portions of the Simplon Tunnel.
In the case of the Rogers Pass Tunnel, however, the pioneer or

* New York City.



DISCUSSION OiSr TUNNEL CONSTRUCTION METHODS 487

aiixiliary tunnel had no relation whatever to drainage, inasmuch as Mr.
apparently ideal conditions were encountered. Furthermore, the posi- °^^ ^^ ^'
tion of the pioneer tunnel, with respect to the main heading, was
such as to render it of comparatively small value for drainage purposes,
had unfavorable conditions of that character been encountered.

A careful study of the paper and other literature appearing from
time to time in engineering periodicals certainly justifies the conclusion
that, although the method used was not, in all probability, the cheapest
that could have been adopted, nevertheless, the results were unques-
tionably consistent with the combined elements of economy and time.

One feature to which attention is attracted is the fact that only
1-h miles of the tunnel will be lined. It would seem that this may
be a possible source of trouble in later years, especially as experience
in the eastern section of the country indicates that, in a number of
instances, tunnels unlined at the time of construction have had to
be widened and lined over traffic at an abnormal expense; and, even
under the most favorable conditions, it would seem that experience
justifies the excavation of a tunnel section of sufficient area to permit
at least of later lining without the necessity of excavating over traffic.

Congratulations are heartily extended to the author for his con-
tribution to the literature of the Society, and primarily for the part
which he has taken in the work under discussion.

C. E. HuLSART,* Assoc. M. Am. See. C. E. — Milton H. Freeman, Mr.
Assoc. M. Am. Soc. C. E., Kesident Engineer on the East River ^^^^ '
Tunnels, joins the speaker in considering the pilot heading somewhat
as a horizontal shaft. Of course, its length is greater than the average
length of shafts in tunnels, but it is much cheaper per foot. To justify
pilot headings on a purely economical basis would be rather difficult.
They must be justified by their convenience and the facilities they
afford for expediting the work. For instance, the Walkill Pressure
Tunnel, one of the Catskill Aqueduct tunnels, more than 23 000 ft.
long, had six shafts ranging from 330 to about 500 ft. deep. Of
course, such a pilot heading would not be applicable to pressure aque-
ducts, but, taking that as an example, for those six shafts at a cost
of $200 per ft. for the sinking and lining (not a bid price, but cost),
such a drift could have been built for one-half the length of the
tunnel, or, in other words, shafts about § or i mile apart could have
been used, instead of | mile apart.

Tunnel ventilation is an interesting subject. The wooden stave
pipe gives a certain rigidity, which was lacking in the 12-in. galvan-
ized-iron pipe used throughout the Catskill Aqueduct. It permits of
the exhaust method, which most tiuinel engineers generally favor.
With the galvanized-iron pipe, the exhaust method is somewhat disas-
trous, because in exhausting, while blasting, the pipe frequently col-

* New York City.



488 DISCUSSION ON TUNNEL CONSTRUCTION METHODS

Mr. lapses. The speaker has seen several hundred feet of pipe collapse,
Huisart. ^^^ ^j^-g ^YiQ wooden stave pipe would not do. In ventilating the
Newark Bay Tunnel on the Passaic Valley Sewer, R. H. Keays, Assoc.
M. Am. Soc. C. E., used a 6-in. pipe, and blew air into the heading
at a pressure of 7 lb. at the compressor, which gave excellent results.
The ventilation was effective for more than 1 mile. The length of
the tunnel was 11 000 ft., and one heading was considerably longer
than 1 mile. The men were never overcome by smoke or fumes.

On the Oatskill Aqueduct, when air had to be driven for some
distance, with a fan which could create a pressure of perhaps only
7 oz., a relay method was sometimes adopted, with one or two fans
in the tunnel for blowing in or exhausting.

The contractors for the Rogers Pass Tunnel made extensive use
of compressed air, a plan which not many New York contractors
would follow, to the same degree. Compressed air is a very expensive
form of power, especially (as in this case) when compressed to 1 000
lb., for use in traction engines, trucks, and blowers. On the Walkill
Pressure Tunnel, which was particularly well planned, some tests were
made with air compressed to 100 lb. and used for pumping purposes.
Considering the whole system, from the power that went into the
motors operating the compressors, to the water pumped at the tunnels,
the efficiency was found to be about 7^%, and that of electric pumps,
in small units, was about 55%; in other words, electricity was from
seven to eight times as efficient as air compressed to 100 lb.

To compress air to 1 000 lb. requires two and a half times as
much power, and it is used in any ordinary motor pump, hoist, or
traction engine at a pressure of about 100 or 150 lb., so that the
efficiency of such air-driven machinery would be about one-twentieth
of that of electrically-driven machinery.

The Rogers Pass high-pressure plant required 1 500 cu. ft. at each
end of the tunnel, or 3 000 cu. ft. of free air raised to a pressure of



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