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THE PANAMA RAILROAD AND TJ^S^RELATIGN TO THE
PANA^IA pÓfAliX
X -i \
Ralph I -'N.
To be Prcsenied FéirtiíKÍ
At intervals since the discovery of th^^Paciñc Çfesëiin Ifey^^lboa in
1513, the improvement of transportation fa^^îitic.s^
of Panama has attracted the attention of variSis"n3iphs%4^:<^í¿tal-
ists.
The first move was the opening of a trail aboupfef- middle
sixteenth century by Spain. It ran from Porto Ben^ an oldifort
about fifteen miles down the coast from Colon, to th^'QÎd City of
Panama. A little later this route was improved upon byNtsntgiihe
Chagras River from its mouth at Fort Lorenzo, about ten milelwpthe
coast from Colon, to Cruces, and from Cruces to Panama Ci^by
trail.
This latter route continued popular until the completion of the
Panama Railroad in 1855, and was used by the gold seekers en route
to California in the early 50's.
The completion of the Panama Canal remains to afford unob¬
structed trans-Isthmian traffic facilities.
The Panama Railroad Company was organized in 1850. Construc¬
tion work began the same year and the road was completed and put
in operation in 1855. The difficulties overcome by the early engi¬
neer parties were almost insurmountable ; in addition to the inevita¬
ble difficulties incident to the unhealthy tropical climate and the dense
jungles, every possible obstacle was placed in their way by the owners
of the pack-trains and the fleets of canoes -who had, with the rush of
the gold seekers to California, built up a very lucrative business. The
fact that the line as built lies directly on the route, and in many places
within the prism of the Panama Canal, as located after the completion
of exhaustive surveys and the preparation of complete contour maps,
speaks for the character of the original railroad location work. The
railroad as first built had a very narrow road-bed both in embank¬
ment and excavation. It was originally built with softwood ties
H -LT 2 0
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2
from southern United States. The torrential rains soon necessitated
the improvement of the road-bed by widening cuts and fills and by
ballasting, and the short life of ordinary timber led to the use of
lignum vitse ties. The road was built 5 ft. gage and has always been
so maintained, all of the tracks on the Isthmus, both Panama Railroad
and Isthmian Canal Commission, now being of this gage.
During French Canal times—1881 to 1904—the Panama Railroad
was controlled by the French Canal Company, but the road has been
practically always managed by Americans. It has always been pros¬
perous and always well enough maintained to safely and expedi¬
tiously handle its business.
The whole organization of the Panama Railroad Company is sub¬
sidiary to the Isthmian Canal Commission, and its chief business is
in facilitating canal construction. The Chairman and Chief
engineer of the Isthmian Canal Commission, is also President of the
Railroad Company, while the Commissioners are members of the
Railroad Company^s Boaí?á of Directors. The General Manager of
the Railroad, who has charge of operation and construction work,
also has the title ot Assi^ant to the President and reports directly
to him.
KEBUILDING THE OLD RAILROAD.
The road is 47.7 miles long. On the advent of the Isthmian Canal
Commission in 1904, it was handling a freight traffic of 17,000,000
ton miles annually. It was early decided to use the Railroad to haul
away the excavated material from the Culebra Cut, as ample space
was found on low ground along the Railroad where dumps could be
developed quickly and cheaply without the necessity of building sep¬
arate tracks to reach them. This use of the Railroad, and the ship¬
ments of all the material and supplies incident to work on the Canal,
increased the tonnage in the years 1906-7 to 42,000,000 ton miles ;
during 1907-8 to 150,000,000, and in 1908-9 to 280,000,000, proba¬
bly the maximum, as the Culebra Cut proper is being shortened by
completion of the Canal near its ends, and the development of large
new dumping ground along the re-located line of the Railroad will
tend to. decrease the tonnage hauled over the present operated line.
To prepare for the great increase in traffic, the Railroad has been
almost entirely rebuilt, and 37 miles of it was double tracked. The
work of rebuilding and double tracking was practically completed at
the end of the fiscal year 1907. The portion double tracked is mostly
built on embankment, so that the grading* for double track was an
unusually simple and economical proposition : namely, that of un¬
loading dirt trains from the Culebra Cut along the main line and
widening the fills thus built sufficiently to carry another track. There
were a few cuts, the larger of which had to be taken out with steam
shovels. In order to avoid delay to the shovel and interruption to
traffic that could not be eliminated from steam shovel work, small
])an cars fold French Decauville cars) of about 1/3 cu. yd. capacity
were used in all cases where the material could be disposed of within
3
reasonable distance. Some of the smaller cuts were taken out by
hand-work with wheelbarrows. For the most part, however, the
work of double tracking consisted of widening the original embank¬
ments sufficiently to support a new track, then moving the new tracks
over to 13 ft. centers by unloading filling from it and keeping it
thrown over to the edge of the bank. The equipment used consisted
of Western dump cars and flat cars unloaded by side plow Lidger-
wood unloader. Both McCann and Jordan spreaders were used for
leveling the fills. In locating the second track it was shifted from one
side to the other of the old main line at many places to better the
alignment, to save cutting, or to improve the vision for safety of op¬
eration. In some places great improvements could be made by sur¬
prisingly small effort. An instance of this is between Juan Grande
FIG. 2. CULEBRA DEPOT—TYPE USED ON THE OLD LINE OF THE PANAMA R. R.
and Gorgona, (Fig. i) where 731 ft. of distance, 104° 34' of curva¬
ture and four ft. of rise and fall were eliminated by building 3,300
ft. of line across a valley which was filled by dumping excavated ma¬
terial from the canal. There were practically no sidetracks on the
old line prior to the Isthmian Canal Commission days, few being
needed. A timetable as of June, 1904, shows ten house tracks, five of
which were spurs, and four passing tracks, the total length of house
and passing tracks being a little less than 10,000 ft. Sixteen house
and commissary tracks have been built, having a total length of
17,100 ft., and eight passing sidings having a total length of 12,300
ft. In addition, 64,500 ft. of yard tracks were built at Cristobal and
La Boca (now called Balboa). The old depots were of shed type 16
ft. wide and 80 to 100 ft. long, one end being enclosed for agent's and
operators office, and the other for freight ; the middle portion served
as a shelter for passengers. These depots were altogether inadequate
4
for the requirements. Twelve new passenger and freight depots
were built at the most important places and five were remodeled.
The Culebra depot is shown in Fig. 2, and is typical of those which
were newly built. These are frame buildings with corrugated iron
roofs, and are 30 by 126 ft., the passenger, office, and freight sec¬
tions being 30, 20, and 76 ft. respectively. The passenger room is not
enclosed, as will be noticed in the view. Five-room living quarters
are provided in the second story for the agent.
During 1906-7 all tracks were laid with 70 lb. Bessemer steel rails,
which replaced the 56 and 60 lb. rails in use on the old road. On the
eleven-mile section from Las Cascadas to Tabernilla, where the-traf¬
fic is most dense, the 70 lb. rail was replaced with 90 lb. Bessemer
steel rail in January, 1908. On all of the curves in this setcion the
90 lb. Bessemer rail has been replaced with 90 lb. Open Hearth steel
rail of carbon content 0.70% to 0.80%, and phosphorus 0.03% to
0.05%. This rail is giving much better service than the Bessemer,
but it has been in the track only since April 25, 1909, so full compar¬
isons cannot as yet be made.
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FIG. 3. WEAR OF RAILS.
Data in reference to rail wear on an 11 degree curve is given in
Fig 3. Manganese steel frogs are used in turnouts leading to and
from the Canal where traffic is most dense. They have proven very
satisfactory and indicate a life of five or six years where Bessemer
steel, spring rail frogs had to be changed every four months. One
regrettable thing in preparing the Panama Railroad for handling the
Canal Commission traffic and maintaining it under this traffic was
the necessity of replacing the lignum vitae ties in the old track with
cypress ties. These old ties had been in the track from ten to thirty
years, and many of them were as sound when removed as when first
laid, but they were all pole ties having a face of from to 7 inches,
and were from 7 it. to 7 ft. 9 in. long. They presented such small
bearing surface that it was impossible to maintain the track under
the traffic that was imposed. Use has been made of them in house
5
tracks and yard tracks, and as fence posts ; of late they are also being
used by the Isthmian Canal Commission in making steam shovel jack
blocks.
The maximum train load on the Isthmus consists of two 120-ton
locomotives followed by a trainload of 4,400 lb. per lineal foot. All
bridges on second main track were built for "Cooper's E-50" loading,
and all of the bridges on the old track were strengthened accordingly.
Pile bridges were used on the second track throughout. In order to
avoid interruptions to traffic a pile driver was spurred on the widened
embankment. Where the bridges were very short, however, the piles
were driven from the machine standing on the old line. There are 65
bridges in all; from 12 to 150 ft. in length. Practically all were too
light to carry the new cars and locomotives. Most of them were
FIG. 4. REPLACING lOQ FT. GIRDER SPAN BARBACOAS, WITH STEAM WRECKERS.
iron or steel spans, ranging from 50 ft. down, and were easily and
cheaply strengthened by driving pile bents under them to shorten
the span. A notable exception was the bridge across the Chagres
River at San Pablo, known as the Barbacoas bridge. This consisted
of six wrought iron through plate girder spans from loi to 109 ft.
long. Instead of double tracking this bridge, a gauntlet track was
laid across it, using No. 12 frogs. The north three spans of this
bridge are over the river channel, and it was therefore impracticable
to put suppOEts under the middle of these spans on account of the
drift-wood during the rainy season. Three new spans were therefore
put in place of those, and a new floor system put in the three old
spans, which were then supported by steel bents placed under the mid¬
dle of each of them. The new girders were put in at the beginning
6
of the rainy season, when falsework could not be held in the channel
except immediately on the down-stream end of the piers, and built
as extensions to them. The new spans were therefore installed in
the following manner: A span complete, including the deck, was
loaded on flat cars and set immediately over the place where it was
to be installed. The new span was then blocked up on the old gird¬
ers and the flat cars taken away. A 75 ton steam wrecking car was
brought up against each end of the new span, and the span lifted
bodily and held suspended in the air, while the entire old span was
pulled down stream onto the falsework. This was accomplished by
two Lidgerwood unloaders, which' stood on the track at the end of
the bridge, and each of which handled one end of the old span. After
the old span was removed, the new one was lowered into place by the
wreckers. The entire operation consumed about four hours for each
span placed. The work was done on three consecutive Sundays.
In Fig. 4 is shown the second span being placed. The total weight
of the span, complete, when handled by the wreckers, was 115 tons.
Fig. 5 shows a plan and section of the old wrought iron girders.
These girders were installed about 1870 ; the exact date is not known.
The majority of the loaded dirt cars handled over the Panama
Railroad tracks are what are called "Lidgerwood Flats.They are
flat cars with a 3 ft. sideboard on one side, and with a 12 in. extension
of the car floor on the other. When heavily loaded, as they usually
are, the center of gravity is about 15 in. from the center of the track,
and about two-thirds of the weight is on one side of the car. This
creates a very peculiar condition for track maintenance. In order to
avoid derailment of these loaded cars it is necessary to adopt 3^4 in.
as the maximum super-elevation for the outer rail on curves, regard¬
less of the degree of curvature. With this super-elevation very few
derailments occur, but with all other track conditions practically per¬
fect and 6 in. super-elevation on an 11 degree curve, five derailments
have taken place at the same spot in one day. This unusual number
was due to the fact that, early in the day, a loaded train with the
heavy side of the car over the low rail, was flagged on the curve, and
in slowing down became derailed, due to the decrease of centrifugal
force, which would have prevented derailment at the higher speed.
While no damage was done to the track by this train, the train crew
reported the derailment and a slow order was placed, with the re¬
sult that within the next few hours and before the cause of the
trouble was discovered, four cars in other trains, especially badly
loaded, were derailed in a similar manner. Reduction in super-eleva;
tion from 6 to 3^2 in. prevented further trouble, although all trains
run slow during the next twenty-four hours while damaged ties were
being replaced.
THE RELOCATED LINE.
In general, the Panama Railroad was built from Colon to Gatun,
a^ distance of seven miles across a salt marsh. Here it reached the
Chagres River and followed the Chagres Valley, keeping more or
FIG. 5. OLD FRENCH PLATE GIRDER BRIDGE.
8
less closely to the river for a distance of twenty-four miles to a poinU
near Bas Obispo, where the Chagres makes a decided turn to run
parallel with the continental divide, while the Railroad keeps its
general direction following the Camacho River up very nearly to the
summit at Culebra, and then, after crossing the divide, it descends
the Pacific Slope in the Rio Grande valley. The Atlantic Slope from
Colon to Bas Obispo is quite flat, the elevation reached at the latter
point being 85 ft. aboye the sea. Since the water in Gatun Lake will
be normally at that elevation, it is apparent that all of the present
line between Gatun and Bas Obispo will be submerged when the lake
is formed. Similarly the lake will submerge the section of track
from IMiraflores to Paraiso on the Pacific side. Moreover, the Rail¬
road now crosses the Canal in two places—once at San Pablo, and
again at Paraiso. The section from Colon to San Pablo—23 miles
long—lies on the east side of the Canal; the middle section—San
Pablo to Paraiso, 17 miles long—lies on the west side, and the south¬
erly section from Paraiso to Panama—7 miles—^is again on the east
side.
These conditions necessitate the construction of a new Railroad to
take the place of the old one from Gatun to Miraflores. The mini¬
mum elevation of sub-grade for this new Railroad through Gatun
Lake (Gatun to Pedro Miguel) has been fixed at 92 ft. above sea
level, except at points opposite Gatun and Pedro Miguel, where the
sub-grade is 95 ft. As the present line between Colon and Gatun.
and also between Panama and Pedro Miguel lies only a few feet
above sea level, it is necessary to begin the relocation at sufficient dis¬
tance north of Gatun and south of Pedro Miguel to attain an eleva¬
tion of 95 ft. on reaching these points. On the north end the new
line joins the old at Mindi—2^2 miles north from Gatun—and on the
south end the junction is at Corozal—4 miles south of Pedro Miguel
•—-3. greater distance being used on the Pacific end because there are
two sets of Locks^—one at Pedro Miguel and one at Miraflores—
making an intermediate lake at an elevation of 55 ft. just south of
Pedro MigueL The entire length of the relocated line from Mindi
to Corozal is 40 miles.
Location parties were put into the field in September, 1906, under
the direction of the Assistant Chief Engineer of the Isthmian Canal
Commission. The location was completed in March, 1907, and the
right-of-way was practically all cleared by the end of April.
From Mindi to Gatun the line lies along a chain of hills, which af¬
fords support to gain the necessary elevation at Gatun. From Gatun
to Bas Obispo the line was located along the east side of Gatun Lake.
From Bas Obispo to Pedro Miguel it will occupy a 40 ft. berme left
in the east slope of the Canal at an elevation of 95 ft. above sea level.
From Pedro Miguel to Corozal it crosses two deep valleys and passes
through the Miraflores ridge in a tunnel; the fills across these two
valleys were made of waste material from Culebra Cut.
On May 23, 1907, the construction of the relocated line was turned
over to the Panama Railroad under the direction of the General
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FIG. 8. GENERAL MAP OF PANAMA R. R.
FIG. 9. EMBANKMENT^ SOUTH OF GATUN—ON SOFT GROUND.
9
Manager. During the fiscal year of 1907-8 work was confined to
three districts where the construction of the new line would mate¬
rially aid the Canal Commission plans. These three districts were as
follows :
First, Work in the vicinity of Gatun in order to abandon the old
railroad tracks which occupy a portion of the site of Gatun dam.
Second, Construction of Gamboa bridge and three miles of track
to open up dumping grounds.
Third, Construction of two large culverts near Miraflores to admit
of enlargement of dumps, and the construction of Miraflores tunnel.
The work in the first mentioned section consisted of building the
new line from Mindi to Gatun and building a temporary track from
Gatun to join the old line at Tiger Füll two miles south of Gatun.
The temporary line crossed the Gatun River and its wide, low valley,
and was so located that the permanent embankment, when built,
would include the temporary fill within its prism.
Gamboa bridge carries the relocated line across the Chagres River.
It is located at the north end of Culebra Cut near Bas Obispo, where
the Chagres River enters Gatun Lake. In the three miles north from
Gamboa the relocated line crosses several streams having large val¬
leys which aflford dumping space for about 10,000,000 cu. yds. of
material. Gamboa bridge made this dumping ground accessible from
Culebra Cut. The bridge is 1,325 ft. long and consists of fourteen
80 ft. through plate girder spans and one 200 ft. through truss of
the Warren type, all resting on reinforced concrete piers and abut¬
ments. The bridge is built for '^Cooper's E-50" loading and under
the 1906 specifications of the American Railway Engineering and
Maintenance of Way Association, The top of rail elevation is
99^ ft. and the lowest member of the bridge is 93/^ ft., that is 8F2 ft.
above the level of Gatun Lake. The French Canal Company had
built a bridge at this place, of which two truss spans, respectively
ICQ and 200 ft. long, were still standing. Although too light for
heavy traffic, they were valuable for construction work. A tempo¬
rary trestle was built from the north end of this old bridge, 18 ft.
centers, from the new bridge to a point beyond the north abutment.
The south end of the old bridge was connected by tracks with the
tracks in Bas Obispo cut ; over this track and bridge, all material
for construction of the piers was handled, and the trestle served in
place of falsework for the girder spans. All erection was done by
the Railroad Company's forces. The truss span was erected with a
locomotive crane on falsework. The girders were shipped to the
Isthmus in three sections each, and were set up and riveted in the
Gorgona shops of the Isthmian Canal Commission. They were
shipped to the bridge site standing upright on flat cars and were
erected by two locomotive cranes, one of which stood on the tempo¬
rary trestle which was connected up with the old French bridge,
and one on the last completed span of the new bridge.
In Fig. 6 is shown the new bridge nearly completed, and the old
French bridge and trestle which was connected up and used for
10
falsework, while Fig. 7, «hows <F.e two locomotive cranes placing a
girder.
FIG 6. GENERAL VIEW OF GAMBOA BRIDGE LOOKING SOUTH INTO CULEBRA CUT.
FIG. 7. PLACING A GIRDER BRIDGE WITH LOCOMOTIVE CRANES.
II
The two 20 ft. by 24 ft. reinforced concrete arch culverts were
built between Pedro Miguel and Miradores to carry the Pedro
Miguel and Caimetillo rivers respectively. The construction of these
culverts allowed the development of dump grounds in the river val¬
leys, and gave access to the north end of Miradores tunnel, work on
which was also carried forward during the dscal year 1907-8.
During the dscal year of 1908-9 construction work was carried
on over the entire line, and continuation of the progress now being
made will see the track connected up throughout by April i, 1910,
except that portion which lies in Culebra Cut proper.
While building a temporary line around Gatun dam, investigations
were made to determine the character of the underlying strata in
the Gatun River valley, across which it was necessary to build the
temporary line. It was found that there was an upper layer of 25 ft.
of clay and sand over irregular alternating layers of very soft clay,
sand and silt, while rock was 200 ft. below the surface of the ground.
Experience in building a short dll across a small valley near the main
Gatun valley demonstrated that embankments could not be built
across these Gatun bottoms at any ordinary slopes, and that the side
slopes would necessarily be as dat as 5 or 6 to i, instead of 2 to i
as originally contemplated and as used elsewhere on the line. The
valley in question is 6,500 ft. long, and the surface of the ground is
8 ft. above sea level. To build an embankment with subgrade at 92
ft. above the sea, with a top width of 40 ft. and side slopes 2 to i,
as originally contemplated, would have required 4,200,000 cu. yds.
of material. To build this embankment at the same height and of
the same top width, but with side-slopes 5 to i, would a little more
than double the embankment quantities, requiring practically
9,000,000 cu. yd. of dll. Investigations were begun, looking to the
abandonment of this enormous embankment. The construction of
a steel viaduct was considered, but the idea was abandoned on ac¬
count of the expense of maintaining it, as 76 feet of the towers
would have been submerged by Gatun Lake.
In February, 1908, parties were put into the deld to seek a new
location further up the Gatun valley. No construction work had at
this time been started between Gatun and San Pablo. The original
location made in this section by the Isthmian Canal Commission
engineerSj^ had skirted along the eastern border of Gatun Lake, fol¬
lowing around the west end of several ridges that are in general
direction perpendicular to the line. A better crossing was found
about four miles up stream, but to go so far up stream to cross the
valley and then to come back again to join the original location
around the west ends of these ridges, made the line very long and
crooked. It was proposed to build the line from Mount Hope (i/4
miles from Colon) to this upper crossing, and to operate a spur
line from Mount Hope to Gatun (5^ miles), but this was abandoned
because it was desired to have Gatun and its permanent activities
on the main line. The desirable thing to do, then, since it was
necessary to go so far eastward to improve the bottom, was to
I 2
keep the line back from the east border of Gatun Lake and to cross
the ridges instead of passing around to the west of them, and then
to join the original location at a point about two miles south of
Bohio, where the border of the lake and the original location turn
back eastward on account of the topography of the country. This
would not introduce any considerable distance, since it would place
the line on the north and east sides of a quadrilateral, along the
west and south sides of which the original location was made.
The ordinary reconnaissance in this country is practically impos¬
sible, but contour maps, showing lo ft. contours below elevation 90,
completed about this time by the Isthmian Canal Commission, indi¬
cated the possibility of such a change, and showed that the ridges
were narrow in places. Surveys were made along the Bohio, Agua
Salud, and Baldo Espino ridges, seeking low saddles where the con-
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tour maps indicated, through which a location could be made. Such
saddles were found and the line relocated accordingly. A further
change was made between Frijoles and San Pablo along the same
lines; that is, moving the line back from the edge of the lake into
the hills. The map of the Canal Zone, Fig. 8, shows these changes.
In addition to greatly reducing the amount and degree of curva¬
ture, these changes in location also give a line which can be short¬
ened five miles by building a four-mile freight cut-off from Mount
Hope to join the line again just north of Gatun River crossing, as is
also shown in Fig. 8. This is the line on v/hich it was proposed to
build and operate a spur track from IMount Hope to Gatun.
SOME UNUSUAL FEATURES IN CONSTRUCTION.
At a point 800 ft. south of the Gatun Station a high embankment
carries the relocated line across a valley 1,600 ft. wide, which joins
the main Gatun valley at this point. Seven hundred feet of this
embankment is from 80 to 85 ft. high, as shown on the map and pro¬
file attached, Fig. 9. The permanent relocated line occupies the
center of this embankment, and along the west side is the tempo¬
rary connection track, known as the ipj per cent line, which leads
from the relocated line at Gatun Station (elevation 95 ft. above sea
level) _to the old line at Tiger Hill (elevation 22 ft.). The valley
which this embankment crosses will eventually be an arm of Gatun
Lake. It was originally planned to build this fill in three decks and
to use the excavated material from Gatun Locks. This material
being entirely rock, side slopes of i^^ to i and top width of 30 ft.
were planned. The base of the fill up to elevation 30 above sea level,
containing 80,000 cubic yards, was placed as contemplated during
the months of September, October, November, and December, 1907.
In the months of November and December, 1907, a connection track
2,000 ft. long was built from the Gatun Lock side in order to place
filling from the second deck, a trestle 30 ft. high being driven across
the embankment at an elevation of 60 ft. above sea level. This
trestle was filled during January and February, 1908, without serious
difficulty, the only occurrence being a slide where the embankment
crossed the old creek bed and involving movement of about 5,000
cu. yds. of material. This was not considered unusual, as it is a
condition commonly met in such work. During the night of March
26th, after completion of the third deck trestle, which was driven at
the elevation of the 1% per cent Gatun-Tiger Hill line, and after
about 100 ft. of this trestle had been filled from the north end (eleva-
tion_90 ft. above,sea level at this point), a very large slide occurred,
carrying the tracks on the first arid second decks several feet out of
line and lifting the ground at the base of the embankment 10 to 12
ft. upwards over and area of about 50 ft. by 150 ft. This slide was
apparently due to the placing of a large amount of filling against
the hillside which rested on an inclined rock surface, causing all the
material above the rock to slip. Up to this time, 166,000 cu. yds. of
material had been placed in the embankment. Dumping on the
14
center line was now abandoned and the bottom of the embankment
was widened by raising the first deck track to elevation 35, and then
throwing it over to the west. This was the condition at the close of
the fiscal year June, 1908. The work was continued along these lines
until in September, when 50,000 cu. yds had been deposited as a
counter-weight along the west side of the fill. During October,
November, December, and January, the fill was brought up to the
level of the third deck, a total of 337,000 cu. yds. having been placed
up to this time. Throughout this process several bad slides occurred,
not through slipping off the steep hillside as at first, but by displac¬
ing the clay which overlaid the rock to a depth of 50 to 80 ft. on the
east side, and from too to 125 ft. on the west. All these slides
occurred toward the west. The counterweight had been added to
during this period and by the end of January it was very large, mak¬
ing, together with the bulging up due to slides, a slope of about 6 to i
on the west side of the embankment. It was now considered safe
to raise the embankment to final grade, elevation 95 ft. above sea
level. On March 21st, when practically up to grade and when the
embankment was considered to be about completed, a slide occurred
to the east, or up-hill side, displacing about 50,000 cu. yds. of ma¬
terial, with a vertical settlement of about 30 ft. for a distance of
FIG. 10. SLIDE IN GATUN FILL.
about 300 ft., as shown in accompanying photograph. Fig. 10. In
Fig. 11 is shown the same embankment a few days prior to the slide.
This was the first movement eastward. The method employed on
the west side, that of building a counter-weight, was now resorted to
'S
on the east side as well, and after continuing this until June ist, fill¬
ing was resumed on the center line, and by June 15th had reached
two feet above final grade, with a top width of 40 ft. and side slopes
that will average about 6 to i on the west and about 3 to 1 on the
east side. The actual amount of material deposited was 528,000
cu. yds. To have built a fill 40 ft. wide on top, with side slopes 2 to
I, would have required 293,000 cu. yds.
FIG. II. HIGH EMB.1NKMENT AT GATUN, JUST PRIOR TO SLIDE.
Fifteen hundred feet south of the high Gatun fill the line turns
sharply to the left and follows along the south side of the ridge,
which extends eastward from Gatun Dam and forms the rim of
Gatun Lake. The line follows this ridge for about four miles, where
it makes another sharp turn, this time to the right, and crosses the
Quebrada Ancha, Quebrada Baja, and Gatun valleys, which con¬
verge into one between here and where the original relocation
crossed between Gatun and Tiger Hill. The south slope of this ridge
is more or less cut up by gullies, and numerous ridges extend out
between these gullies. The method of construction has been to build
as much as possible by benching into the side hill and casting over
with steam shovels, driving pile trestles across the intervening
gullies.
A temporary trestle 250 ft. long and 70 ft. high across one of
these gullies is shown in Fig. 12. By this method the track is pushed
ahead iVith the least possible amount of work until the large valleys
are reached, when the entire side hill along the ridge can be de¬
veloped into a borrow pit for obtaining material to make the em-
i6
bankment, at the same time grading a very good roadbed in solid
rock excavation, safe from slides, where the completed track will be
located.
FIG 12. TF.MPORARV TRESTLE, .^LONG GATUN RIDGE.
As the new line lies so far from the present one in the section
south of Gatun, it is necessary to build that part of the line between
Gatun and Frijoles (12 miles) by working south from Gatun and
north from Frijoles, no connection tracks being possible from the
old line. This kind of construction is most difficult in the tropics,
owing to the dense growth of vegetation and the difficulty of getting-
material and subsistence supplies. The method employed is to estab¬
lish camps as far ahead of the tracks as possible, so as to have the
17
cuts excavated in advance of pile driving which is necessary across
the numerous wide valleys. Pile driving is hastened where trestles
of from ^ to % of a mile in length are required, by laying a track
across the valley and backing a pile driver across on this track, then
starting it driving from the far end to meet the driver which starts
at the end of the track, the track in the bottom being used mean¬
while to supply the materials to the two drivers.
FIG. 13. SHOO-FLY LINE USED TO WORK PILE DRIVERS IN LONG TRESTLE.
In Fig. 13 is shown two pile drivers about to meet in the middle
of a 3,000 ft. trestle and also shows at the left the temporary track.
A Lidgerwood unloader is usually employed at the end of the track
in such cases to let down the loaded cars, and to pull up the empties
after they have been placed by the smaller engines and unloaded
on the lower track.
During the dry months, January to May, 1908, excavation of the
Miradores tunnel bore had been practically completed, and tempo¬
rary timber lining had been placed throughout almost the entire
length.
The north 400 ft. of this tunnel passes through solid rock, and the
south slopes of this rock lies at about an angle of 45°. The excava¬
tion of the south portal of the tunnel so disturbed the equilibrium
of the earth which forms the south side of the Miradores Ridge,
which the tunnel pierces, that during the months of July and August
the entire side hill, involving"about 200,000 cu. yds. of material, began
moving southward along the axis of the tunnel and also slightly
^¡¿ÍÍ^^Mmrrrj'yr^MXMm^Mmjyw «WZ«#î<W^»»»»»»>Î9S^WWV»»zâwzvvsZ'^ÎÎÎé
EARTH SECTION.
Distance, of 2<4-t from floor of Tunnel to Ton-of Rail
made up os follewa:- '
Standard 90 lbAS.C.E. Roil V Tie Holes o'- b|
Cr'eosoted Tie «'«ft'xs-e* »paced ei" c.t.c o- e"
Sravel BaUast toelew boltorn of Ties 6- s*
Coarse Recb Roadbed e'- ^
Guard Rail te extend ÖO' beyond RsrtQl». .
Tía» spaced 20 per Rail Ieng1h.(»»' of TraeK)
^IG.
14.
ROCK SECTION.
LUMSCR.
BILL OF MATERIAL.
, ONE SET.
SIÄE
N«
fIBCf»
FtB.M,
%4
%
4-ao
IV'X iCx 10'
1
izVixS 1%'
1
Id«.«-
TOTi-U.
Sd%>0
PANAMA R.R.CO.
RELOCATED LI NC.
Office of Chief En^'r; Colon, R.P
TIMBERING VLIHING
FOR THE
M/ffAFLOi?£S TU/ifi£L.
Drawf? by H'lC-Vc.tc. 5.
TfAced by O'b'f*
A^rPROVCO
Chief En^n
Scole- |-r-o"S.
Date Sept 18, 'op.
Checked by
File NS ^315-6
M
00
TUNNEL UNING.
19
eastward, at an angle of about 20° from the direction of its axis.
This carried the earth section of the tunnel with it and literally
twisted the tunnel to pieces. The timbering in the earth section, 200
ft. long, collapsed in September. The rock section, 421 ft. at the
north end, was not affected and was lined with concrete during
September, October, and November. Work was discontinued in the
earth section until the beginning of the dry season, January ist, when
the tunnel was again opened up on the original center line and grade,
and was completed in April, 1909.
FIG. 15. SLIDE ON SOUTH SIDE OF MIC.\PTON RIDGE, SHOWING SOUTH END OF
TUNNEL.
The reinforced concrete lining of the earth and the rock sections,
also the roadbed as built, is shown in Fig. 14. A track was laid and
heavy rock placed to refill the hole in the south side of the hill,
caused by the slide. The illustration. Fig. 15, from a photograph,
shows this work about completed, and also shows the extent of the
slide. The small summit at the right was originally ahout on the
center line. The escarpment on the side of the main hill indicates
where the slide broke off. The tunnel was lengthened 50 ft. at the
north end and 91 ft. at the south end, to provide for flatter slopes
on the sides of the hill due to slides. Its length on completion was
736 ft. from portal to portal, instead of 595 ft. as originally con¬
templated.
20
BRIDGES AND CULVERTS.
On the completed line there will be two steel bridges carried on
reinforced concrete piers and abutments. One of these, spanning the
Chagres River where it enters Gattin Lake at Gamboa, has been
described above. The other will be a bascule bridge at the Gatun
River. All of the other rivers and streams will be carried through,
culverts below sub-grade. These culverts are being built from 15
to 20 ft. above the bottom of the stream. The backing up of water
FIG. 16. TVITC.M. T.\SK WORK.
is of slight importance for two reasons : First, the land is unculti¬
vated and is already owned by the Isthmian Canal Commission, or
will have to be purchased before being submerged by Gatun Lake.
Second, when the lake is formed, all land on both sides of the line
below elevation 85 above sea level, will be permanently flooded. By
placing the culverts high against a rock side hill, good foundations,
without piles, are often obtained, where it would have been neces¬
sary to go to great expense had the culverts been located in the
bottom of the valley. Furthermore, with embankments having side
slopes of 2 to I, each foot the culvert is raised shortens it by four
feet.
Three types of concrete culverts are used ; reinforced concrete
arches, reinforced Ixixes. and vitrified pipe culverts. Gravel con-
» /Ofy // A
\ rSfmam SAatv/ ^»eA Ci/^, 4/4^ y»r//e0^
■ A A. A /►." /
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If fractr /# tocmtoof hotiaoott Oo/tof anrt Main Lin*, Búñaonrtra
shait b* mainfainatt.
for Stontfani Thoek Conafruction a** Shoot Mo. tSiZO.
Mr âuAnrar^af//fy/S/o/o* Z /
A ûrjr A , A /it
troamSMr*.'fartnCi^t S.'ofi* H /
r/a/t^r t I, ti, /
for Ory ftitâ.S/ofam tJt.' / arret A ' iO/t.
Mr Submoraaa fit ta. Staoa 2. t anet/or h a iah ta,
from i O' to Jû - '-A " tO'
A SO' A SO--A - tS'
arar SO' A " 20'
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PANAMA H PI CO
STAMOA>lOS.
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STANOA>^D ROAOeeO
roq
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ÄiOl« -O'
O rown by, r. iLti . _
Trac*it by Xjíí.. .
Chizt'Cpflinttr
Ofli« MauliSt
Appro*'«ii- ^ Chifkccl by
' Aá,.¿£POffJ
Flit fio i5il5.
FIG. 17. STANDARD TRACK CONSTRUCTION.
H CAT UN 'Aa:i
PAMAM A R. p. CO.
STAM OAf^OS.
Office Chief E!n3¡ncec Colon, F?. P.
STAM DARD DEPOT.
TVPE 'A:
Drown by
Scftie 'A'• r-o:
Dottf. «1?^».
Checlfed by
Traced by.
Appro^.-j;
/k
Chief fn^ineer File Mo ir'IZ-l
to
to
fig, i8a. standard depot.
r
-4^-
Pfatform.
C^r9cr%fm - '^£9%% mé Prm^ht /facfn.
>
«k
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fi^ight ^«om.
C*rtettAf/ocr—SíSfí. móort Office f/vor.
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V*raní/ír. "i
SccoNo fZoo/t Plan.
See/Poo/rt:
39'-a'
fi-a-
PAMAMA R. R. CO.
STAMOAi^OS.
OFfic« Cti)«f EnginacT Colon . F^,r.
SXAMOARD DEPOT
TYPE "A"
Drown by ah.u
Traced by jciii.
Approve«! -
Chief Cngineor
S«:ala. 'A'-l'-O.' ■
Dote. _a*et xíSSi-
Ch«ck«d by.
File Mo. 15122-2.
Ca>
No 2»f2flhftoU
fig. i8b. plan of gatun depot.
25
Crete has been used almost exclusively, the gravel being obtained
from deposits in the Chagres River.
FIG. 20. VIEW OF STATION AT GATUN.
On all of the smaller cuts, and in many cases to open up for a
temporary track to start steam shovels, the so-called "task system"
of labor is used. By this method the laborer is paid for carloads of
Panama r.r.co.
OIAQRAMS SHOWING PERCENTAGE OF COMPLETION OF THE RELOCATED LINE.
ri»Col Y»or'OÎ"08
Fiscol Y«or '08-'0»B
FIG. 21. DIAGRAMS OF WORK DONE.
material moved rather than for his time. A price of 8, 9, and loc
for each Decauville car (about 1/3 cu. yd.) was fixed upon, depend¬
ing on the length of haul and the inacessibility of the work. No
FIG. 22. SHOWS ORDER IN CONSTRUCTION IN HIGH EMBANKMENT.
27
classification of material is made, as the Railroad Company does all
blasting necessary to get the rock into pieces small enough to be
handled by hand. A West Indian laborer can be employed to espe¬
cial advantage by this method. A number of negroes co-operate,
some doing digging and loading, and some dumping and spreading.
The Company requires that at least fifteen cars be loaded by each
man for his day's work. Frequently this 'hask" will be finished in
six hours, while on the hourly basis it would hardly be done in nine,
A typical ^hask" gang at work, is shown in Fig. i6.
The section of roadbed used is rather unusual, owing to local
conditions. Ample width is required in excavation, owing to the
enormous rainfall, and it can be provided without extra expense, as
the embankment quantities are so largely in excess. The extra
width and flat slopes provided on the embankment are on account of
their being submerged, as indicated on the standard roadbed plan.
Fig. 17.
Two types of depots are provided, as shown in standard plans,
Figs. 18 and 19. One type "A" depot, has already been built at
Gatun, as shown in Fig. 20.
The following table shows comparative data concerning the
present operated and relocated lines.
P///5/C/1L. sr/ir/sr/cs.
OLD ¿/A/D
/fFLOC/tTfO L/A/F.
D/sTance Co/on /d Fbnama
47.^7 m//e&
46./Smf7es
Troc/fs.
Ocub/e TrocX 64- mt/fs
Sirt<t/e TrocX—J4.63mt/e^
G/na/e 7facF
G<7uepe of Troc/i
s-a"
We/off and Secfon of/fod
/9TrvcA- 90^A.S.c.£:
7Û^AS.C£.
^md of GoZ/gs"/:
Gnaix&Z
G roye/
Tbia/ /ftse and fd//.
4L7.Ó Feet
2Û3.Û fèet
fZax/n^om Gnod/ent-^/Vorih 3oi/nd
/. £0 L' Oorr?p.
û. 4£'y^ Comp
„ // ~ Sovfh Goond
/.4£y'> Comp
/ 2 5 '/^ Comp
r
42° 2/'
3 34° 29*
Z'
264'' 4.2'
4/9°£7'
3"
£23° £8'
382° /£*
r
34/° /£'
262° £4'
D/sfr/ duf/on
5"
£37° 4d'
/Û/° 60*
of
6'
333"' £/'
49/° /£'
C/ar\/ofunG
7^
226° /3 '
/Vone
6'
33/° 49'
A/one
d'
322° 30'
A/one
/o"
3/3° 4/'
A/one
/r
/££''47'
A/one
7070/444^" ó/'
/93/°£2'
FIG. 23. TABLE OF COMPARISON OF OLD AND NEW LINES, FOR ALIGNMENT, GRADES,
DISTANCES, ETC.
The diagram, Fig. 21, shows the general progress of the work to
date. The new Railroad will be practically completed during the
present fiscal year, except building the two miles across the Quebrada
28
Ancha, Quebrada Baja, and Gatun river valleys. Track will be car¬
ried across these valleys on temporary trestles at a minimum eleva¬
tion of 50 ft. above sea level, and the embankments will be built by
the methods shown on cross section. Fig. 22, the successive opera¬
tions being numbered from i to 4. The total yardage in these em¬
bankments will be about 3,500,000 cu. yds. The minimum eleva¬
tion of the old Railroad in the Gatun Lake region is 20 ft. above sea
level. The present line will be used until the water in the Gatun
Lake reaches this elevation of 20 ft., when the new line will be put
into use between Gatun and Bas Obispo, where a connection will be
made by building a trestle across the Canal, as shown in Fig. 8. The
old line will then be used from Bas Obispo to Paraiso until the
Culebra Cut is completed.