|Oneonta Bluffs ca. 1908
||Oneonta Tunnel ca. 1920
|Oneonta Tunnel ca. 1995
||Oneonta Tunnel September 2,
|Oneonta Tunnel March 21, 2009
||Oneonta Tunnel March 21, 2009
part of a project to restore Oneonta Tunnel (let's hope they
don't "restore" it the same way they "restored"
the Mosier Twin tunnels with it's hideous rock catchement)
Oneonta Tunnel was daylighted August, 19, 2006. For the first
time since it was filled with debris in 1948, daylight could
be seen through Oneonta Tunnel. Oneonta
Tunnel excavation pictures here.
March 21, 2009.
The grand reopening of Oneonta Tunnel. A beautiful job of
restoration with excellent attention to original details.
reopening pictures here.
Formerly carried the Historic Columbia River Highway, Multnomah
Country, Oregon, through a rock outcropping immediately east
of the mouth of Oneonta Gorge, beginning east of milepost
Date of Construction:
Samuel Lancaster, Consulting Engineer for Multnomah County
and Assistant State Highway Engineer, Oregon State Highway
S. P. White and Co., Vancouver, Washington, contractor
Oregon Department of Transportation
None; closed in 1948
One of four tunnels on the Historic Columbia River Highway.
The Historic Columbia River Highway's alignment
from Crown Point, milepost 23.9, to Horsetail Falls Bridge,
milepost 34.6, takes the highway along one of the largest
concentrations of high waterfalls in North America. Near its
eastern end lies Oneonta Creek and Gorge. The name ''Oneonta,''
according to Oregon Geographic Names originates in Oneonta,
New York, and means "place of peace". The Oregon
Steam Navigation Company ran a sidewheeler named Oneonta on
the Columbia, above and below its cascades, in the 1860s and
187Os. Oneonta Creek and Gorge probably were named sometime
after the boat's construction.
In 1914, the Multnomah County Road Department
and Samuel Lancaster sought to align the route so that it
brought travelers to the mouth of Oneonta Gorge, a canyon
so narrow that its basalt walls almost touch as they rise
two hundred feet above the creek. Subsequently, the county
built Oneonta Gorge Creek Bridge. Carrying the alignment past
a nearby 200' bluff, a continuation of the Oneonta Gorge,
proved more difficult. In the 1880s the Oregon-Washington
Railroad and Navigation Company (OWRN) had laid out its route
along the Columbia River's south shore. Much or it was along
the old Troutdale to The Dalles road begun in the 1870s. The
OWRN's right-of-way crossed Oneonta Gorge Creek then passed
through a narrow opening between the river and the bluff before
continuing east. With the close proximity of the river and
the cliff, there was no additional space to permit carrying
the HCRH around the outcropping.
Determined to include Oneonta Gorge and
nearby Horsetail Falls as two of the natural beauty spots
on the HCRH's route, Lancaster resolved this dilemma by having
a tunnel bored through the outcropping.
Plans stipulated creating an alignment that included a bridge
over Oneonta Gorge Creek parallel and to the south of the
railway span, and continuing east through the rock wall via
a 125' tunnel. The Multnomah County Road Department called
for bids in late 1913, and by the end of the year it had received
contract proposals from 12 firms. Of these, S. P. White and
company of Vancouver, Washington, had the low bid of $30.00
per linear foot of excavation on the tunnel, with a 75 ¢
per cubic yard charge for enlargement. White's construction
engineer, G. M. Pitts, had widespread construction experience
on the West coast and in the Intermountain regions of the
United Staten. He had operated machinery in 1899-1900 on a
tunnel for the Great Northern Railway, was concrete foreman
in 1901-02 for the Montana Central Railway's Wicks Tunnel,
in 1903-04 for the Great Northern's Tunnel under Seattle,
and in 1909-10 for the Milwaukee Railroad. He had most recently
worked with the Pacific Bridge Company, which received contracts
to construct many of the bridges built along the Multnomah
County portion of the HCRH.
DESIGN AND DESCRIPTION
The Oneonta Tunnel consisted of a 125'
straight bore through a 200' tall outcropping of Columbia
River basalt. It measured 20' wide with a vertical clearance
of just over 19' (a radius of 9'-10" measured at 9'-2-1/2"
from the floor). No written records document Oneonta tunnels
construction chronology, but extensive information is available
on how contractors bored Mitchell Point Tunnel and the Mosier
Twin Tunnels also on the Historic Columbia River Highway.
At Oneonta, S. P. White Company most likely
began work early in 1914. The material was Columbia River
basalt: with frequent cleavage places, and commonly known
as ''dice'' rock, because it broke up unto small fragments
when it was blasted. The heading, or top portion of the bore
was taken out first, followed by the bench. Blasting crews
used extreme care when working near the outside wall. Because
of natural conditions: they could only retain an 18' wall.
Rock formations contained many large fissures. According to
historian Oral Bullard, "The problem at the Oneonta Tunnel
Was that in order to prevent thousands of tons of rocks from
cascading down into the railroad tracks when the blasting
began it was necessary to go to considerable extra work to
strengthen the cliff before digging into it." Lancaster
devised a plan whereby White's crews injected concrete into
crevasses in an attempt to stabilize the material.
Cutting Oneonta Tunnel was a tedious process
that involved the skill of an experienced explosives expert.
The arrangement of blast holes, and the sequence of explosions,
most likely using 40 percent dynamite and black powder, were
the key to precise boring. At Mitchell Point, construction
engineer John Arthur Elliott wrote that to ensure that crews
did not collapse the outside wall,
The lower outside lift hole was dropped
one round back, leaving each time about 3' of the heading
next to the thin wall, thus increasing the effective thickness
of the outer wall. This lift hole was always one round behind
until all danger of breaking out had been passed
firing order was controlled by varying the length of the fuses.
shorter fuses were used in the center, and cut holes and longer
fuses in the lift holes. In this Way, the center section was
broken before the heavier charges in the lift holes exploded,
which made the work of the lift holes easier. By holding the
outside lift hole back one round, the necessity of breaking
to a wall on both sides was eliminated, and the explosives
broke out along diagonal lines converging towards the powder
charges, which also made the heading easier to break.
At Mitchell Point, the contractor limited
hole depth in the heading to 4'. Crews used 11/2 sticks of
40 percent dynamite to spring each hole, followed by a per
hole charge of 16 to 20 sticks of the dynamite. Each explosive
round moved the bore along about 4-1/2'
After detonating the charges, crews loaded
the heading material into ore cars on tracks and dumped the
material out the portals. Crews trimmed the roof with picks
and hammers after each shot, and then pilled or stripped off
the bench. They used two sticks of 40 percent dynamite to
spring each hole and followed this with loads of 18 to 22
sticks. Crews loaded, or mucked out, the bench material in
the came manner as the heading, dumping it out the portals.
A photograph dated April 25, 1914 showing
dozens of onlookers at Oneonta tunnels west portal also marks
the progress of crews lining the tunnel with lumber sets and
lagging. Samuel Lancaster wrote Multnomah County Roadmaster
John B. Yeon in March 1914, urging construction of a lining
for the tunnel because of frost action on the porous and seamed
rock at Oneonta and ever present moisture. He worried about
the safety of motorists who might receive serious Injuries
from falling rock inside the tunnel. In the 1910s and 1920s,
most motorists would be vulnerable even inside their automobiles
because most vehicles used soft collapsible tops.
The S. P. White Company completed the Oneonta
Tunnel during 1914 at a cost of $6,684.88. This included $4,140.00
for cutting the tunnel, $523.05 for excavating the portals,
and $1,723.29 for 61,546 board feet of timbering. The tunnel,
however, was not immediately opened to traffic. The Construction
Company of Portland did not complete an 80' reinforced-concrete
deck girder bridge over Oneonta Gorge Creek near the tunnels
west portal until later in the year.
REPAIR AND MAINTENANCE
The Oneonta Tunnel served on the Historic
Columbia River Highway from 1914 until 1948 when a highway
realignment bypassed it. Maintenance records for the tunnel
do not survive, but drawings from 1931 suggest that it was
relined that year, most likely because the original timber
sets and lagging had rotted from moisture penetration. A comparison
of lining plans for Oneonta Tunnel and plans for the 1920-21
lining of the Mosier Twin Tunnels shows striking similarities.
The new lining was probably a replication of the original
construction. It consisted of 12" x 12" timber sets
spaced 4'-0" on centers for the heading portion and 6"
x 16" sets on 4'-0" centers for the vertical walls
riding on 12" x 12" sills. The lagging consisted
of 4" x 6" Douglas Fir boards laid horizontally.
Up the vertical walls rode four 2" x 12" timber
guard rails, spaced 18" on centers, and running the tunnels
length. Four 10" x 12" sets placed vertically at
1" spacing and four pairs of at least 12" x 12"
stacked timbers placed horizontally above them formed the
tunnel portals (an additional, or third timber was stacked
above the outside-most set of headers). Finally, timber inclined
endposts finished the wooden portion of the portals. A dry
masonry wall dating from the tunnel's original construction,
framed the wood. The 1931 plans called for extending the bottom
two plank guard rails outside the portals at a 450 angle,
running about 4' to connect with 12" x 12" posts
as a continuation of standardized post and plank guard fences.
These were never constructed.
Oneonta tunnels lining reduced its clear
dimensions. Its roadway width became 16'-9". Horizontal
clearance at the curb line was about 10' and 16' at the centerline.
By the mid-1930s, with greatly increased traffic volume, and
larger vehicles, Oneonta tunnels vertical and horizontal clearances
were too small to safely accommodate two-way traffic. In July
1936, the Oregon State Highway Department installed traffic
activated one- way stop-and-go signals at the tunnel portals,
temporarily solving the traffic safety problems. The department
also installed similar signals at Mitchell Point Tunnel in
1938 and at the Mosier Twin Tunnels in the 1940s.
Rock fall due to frost was a continual
problem at Oneonta Tunnel. Chunks of basalt filled the cavity
between the tunnel bore and the lining and dropped on the
roadway at the portals. The greatest concern was the perennial
covering of the OWRN (later Union Pacific Railroad) main line
with rock tumbling off the cliff. Not only did it often close
the track to traffic, it cumulatively weakened the outer tunnel
wall, threatening eventual collapse and possibly burying the
main line for an extended period. The Union Pacific also worried
about a disastrous rock fall and track closure if one of its
large articulated steam locomotives happened to derail near
Oneonta Tunnel and slam into the cliff.
In 1948 the railroad saw an opportunity
to end its Worries about the tunnel by moving its trackage
north of the cliff on fill dredged from the Columbia. This
created room for the highway department to re-route the HCRH
around the cliff on the old railroad right-of-way. The state
then mothballed the tunnel with fill to prevent continuous
raveling and possible collapse. The highway department constructed
a new bridge, on the old railroad span's original piers as
part of the realignment, and retained the old bridge and adjacent
abandoned roadway as a parking area for travelers to Oneonta
Gorge. In the subsequent four decades, vegetation has completely
overtaken the Oneonta Tunnel portals, leaving many a person
to ask why the old Oneonta Gorge Creek span is a bridge to
Excerpted from Historic American Engineering
Record, Oneonta Tunnel, HAER 0R-OR-36-L.
Historian: Robert W. Hadlow, Phd., September
Transmitted by: Lisa M. Pfueller, September, 1996.