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BNSF North SIG Intermodal Improvement Project
Seattle, Washington
By
Charles E. Burnham, P.E.
David Evans and Associates, Inc. Trans-Pacific Trade Center Building 3700 Pacific Highway East, Suite 311
Tacoma, WA 98424 Phone: (253) 922-9780 E-mail: [email protected]
Danniel J. MacDonald, P.E.
BNSF Railway Company 1313 West 11th Street Vancouver, WA 98660 Phone: (360) 418-6415
E-mail: [email protected]
ABSTRACT
BNSF Railway Company (BNSF) wanted to increase capacity and efficiency at its Seattle
International Gateway intermodal (SIG) facility by installing four wide-span, electric, rail-
mounted gantry cranes. The project required complete redevelopment of an existing 13-acre site
known as North SIG. Major project challenges included relocation/undergrounding of a City of
Seattle electrical transmission line, soft soils, the addition of two power substations to serve the
site lighting and gantry cranes, high groundwater, and on-site stormwater treatment.
The new facility accommodates four wide-span, electric, rail-mounted gantry cranes and six rail
spurs that can store a complete unit train, which increases capacity at the SIG facility by almost
50 percent. The new cranes are capable of stacking containers as well as loading and unloading
trucks and railcars. The cranes have improved throughput at the facility by approximately 30
percent, supporting the growth of international commerce at the Port of Seattle.
The zero-emissions cranes are significantly wider than traditional cranes, spanning three tracks
and associated container stacking and truck transfer areas. They reduce the need for diesel trucks
to move containers within the facility and decrease the facility's impact on the environment.
Additionally, the new cranes regenerate power each time they lower a load and are quieter than
traditional cranes. BNSF is the first railroad in North America to install these cranes.
PROJECT GOALS
BNSF wanted to enhance the facility performance at the SIG intermodal facility. The North SIG
site was under-utilized and inefficient. The major goals of the project were to improve site
efficiency and throughput capacity; lower operating costs per unit handled, and meet budgeted
capital and life-cycle costs. In order to meet the goals, the site required complete redevelopment
into a modern state-of-the-art facility capable of handling complete container trains at one time.
Figure 1
Figure 2
Figure 3
In addition to increasing track and container storage capacities, BNSF wanted to improve the
operating performance of the facility and decrease the time required to turn container trains
around. Both site improvements and new equipment contributed to meeting the goals.
SITE HISTORY
The project site has been in railroad use for nearly 100 years. The Milwaukee Road used the site
for freight handling, as a Trailer on Flat Car (TOFC) facility, and equipment maintenance yard
from 1916 until 1980. The Burlington Northern Railroad and successor BNSF used the facility
for TOFC and container loading, and for equipment storage and repair in support of their Seattle
International Gateway (SIG) intermodal facility until the construction of this project. An aerial
view of the site prior to construction is shown in Figure 1 and ground perspectives in Figures 2
and 3.
The facility was modified several times during its
history, which presented a number of challenges to redevelopment.
The site had substantial undocumented buried building foundations left in the ground during
previous modifications. There were a number of
active and inactive utilities including water and sewer,
a large sewer force main along the entire westerly side
of the site, and overhead power distribution and high
mast transmission lines. The Seattle City Light power
Figure 4
Figure 5
lines presented two of the largest challenges for the project.
The transmission line limited the construction of
improvements within its minimum clearance zone. The
distribution line crossed the middle of the proposed facility
and needed to be placed underground or completely
rerouted around the site. The transmission line is shown in
Figure 4.
Existing storm drainage on the site consisted of various catch basins connected to the City of
Seattle storm drain system. There were no stormwater treatment facilities due to the age of the
facility. Much of the stormwater that fell on the site simply infiltrated into the gravel surface or
evaporated. The existing system was largely abandoned and replaced as part of the
redevelopment.
PROJECT ELEMENTS
A number of project elements were addressed to
successfully bring the project on-line. Site
redevelopment included complete demolition of
the existing facility; relocation and protection of
major utilities; construction of track, pavement,
storm drainage, crane rails, power and
communication duct banks, site lighting; and finally, erection of the gantry cranes. The new
facility is approximately 1,900 feet long and 300 feet wide. See Figure 5.
Track: Six new intermodal tracks were constructed with a total capacity of 7,800 feet to handle a
complete container train within the intermodal yard operating area. The tracks were constructed
with concrete ties and 141-pound welded rail. In addition to the intermodal tracks, an
approximately 2,300-foot-long car maintenance track was completely rebuilt along the length of
the facility on the westerly side.
Pavement: The initial design criteria for the pavement specified asphalt concrete with a 20-year,
100,000-cycle service life capable of supporting 262,250-pound axle loads generated by rubber-
tired top-pick container handling equipment. Due to the poor soils underlying the site and the
extreme heavy design loads, the recommended pavement design was 12 inches of structural base,
6 inches of crushed surfacing material, and 21.5 inches of asphalt concrete pavement. By
reducing the number of anticipated top-pick equipment cycles to less than 1,000 cycles and the
service life to ten years, the recommended pavement structure was reduced to 7 inches of asphalt
concrete, 6 inches of crushed surfacing, and 12 inches of structural base material.
The reduction in service life under top-pick equipment loads was supported because during
design, the proposed operation of the facility was modified to use large gantry cranes for most
container handling operations. This meant that there would be only occasional use by top-pick
equipment during the life of the facility. Nearly all of the equipment loads on the pavement will
be generated by trucks hauling containers. Therefore, actual service life of the pavement is
expected to be substantially more than ten years.
Grading and Storm Drainage: The site is located in an area of high groundwater due to its low
elevation and proximity to Elliott Bay. The site and the surrounding area sit on hydraulic fill
placed in the early part of the 20th century. The soils are fairly weak and poorly drained. In
order to provide adequate support for pavement, intermodal tracks and crane rail grade beams,
site grades were raised 2 to 2.5 feet above existing ground. Raising the site also provided
improved storm drainage.
Figure 6 Figure 7
Figure 8 Figure 9
Existing concrete and asphalt pavements were salvaged and crushed for reuse on the project as
select fill. Reinforcing bar in the concrete pavement was salvaged and recycled. Figures 6
through 9 show pavement demolition, crushing and reuse on the project.
To accommodate container
storage, the maximum grade in
container storage areas was
limited to 0.5 percent. Track
and crane rail grades were
limited to 0.30 percent. This
presented some challenges to
storm drainage systems for the
facility. Very tight controls on
paving operations during construction were required in order to meet the grading tolerances.
The north half of the site had an existing drainage system connected to an operating City of
Seattle sanitary sewer line. The City required detention but no treatment for this portion of the
site. Treatment was not required, since the water was sent to a city sewage treatment plant prior
to discharge into Puget Sound. Detention was necessary to accommodate an undersized city
sewer line. Detention storage volume was accomplished by using oversized drainage lines on the
site in combination with a flow restrictor manhole immediately upstream of the connection to the
city sewer system.
The south half of the site required stormwater treatment, but no detention. Two alternatives for
stormwater treatment were considered.
Figure 10
Figure 11
One option was a system of several large cast-in-place concrete wet vaults. Typical wet vault
size needed to be approximately 110 ft. x 25 ft. x 10 ft. deep. The vaults need to be capable of
supporting the 262,250-pound axle loads of the top-pick container handling equipment.
Dewatering was required to construct these vaults.
Due to the size, cost and constructability issues associated with the wet vaults, a second type of
system was considered and ultimately used for the project.
The stormwater treatment selected for the project was a two-stage storm filter system. The
system included a vortex-style manhole to separate solids from the stormwater and a filter vault
to collect other contaminants. The footprint of the total system was approximately 10 percent of
the size of the wet vault systems and could be located outside of the area that would be used by
the top-pick equipment. Including capital and maintenance costs for
the first ten years of facility operations, the two-stage storm filter
system is estimated to save nearly $1 million compared to the wet
vault system.
City Light Distribution Line Relocation: A major Seattle City
Light distribution aerial line crossed the site at approximately the
mid-point. This line was placed underground to eliminate the only
overhead conflict on the site and allow the redevelopment as a crane-
served intermodal facility. Approximately 330 feet of distribution
line was placed underground in a concrete- encased duct bank
constructed to meet City Light specifications. The work also included installation of several large
laminated wooden power poles, large electrical vaults and demolition of the existing lines across
the yard. Figures 10 and 11 show the underground duct bank and one of the vaults during
Figure 12
construction. Note the dewatering system that was required for nearly all of the underground
work on the entire site.
Crane Rails: Two pairs of 175-pound crane rails were constructed on 1,300-foot long grade
beams. The crane rail gage is 123.5 feet. Figure 12 shows a typical cross section of the yard with
cranes, intermodal tracks, truck lanes and container storage areas. As part of the crane rail
construction, concrete encased electrical and communication duct banks were constructed along
each of the outside crane rail grade beams. The duct banks carry power cables for the cranes, site
lighting and communication cables, and fiber optics for site and crane communication, and
operation controls.
Site Lighting: High mast lighting was selected for the project to illuminate the yard and track
areas. The lighting design utilized high-pressure sodium fixtures with hoods and lenses designed
to limit light scatter to office, commercial and residential properties immediately adjacent to the
easterly side of the facility.
Gantry Cranes: Four rail-mounted, wide-span, electric gantry cranes were purchased from
Kone Cranes. BNSF was the first railroad in the United States to install these cranes. The wide
span was selected in order to span over multiple tracks, truck lanes and, container storage areas.
The cranes accommodate four high container stacking.
Substations and Duct Banks: Two electrical substations were constructed for the project. One
serves the site lighting and general power demands. The other serves the power needs of the four
gantry cranes. The substations were constructed outside of the operating area of the terminal. All
electrical and communication lines for the facility were placed underground to avoid conflicts
with operations.
SUSTAINABLE SOLUTIONS
The North SIG Intermodal Improvement Project is an example of BNSF’s continued dedication
to sustainability in their operations and capital projects. The simple fact that the project
redeveloped an existing BNSF facility from a low production operation into a very high
production operation greatly reduced development impacts and a much improved carbon
footprint. A number of the elements of the project contribute to a low impact sustainable solution
to upgrading BNSF’s North SIG Intermodal Yard. The most significant are:
Gantry Cranes: The Kone style gantry cranes selected for the facility are zero emission cranes
and are quiet. They provide more operational flexibility and efficiency to container handling by
performing loading for both truck and rail cars. They are able to spot containers into storage
anywhere on site up to four containers high. The need for diesel-powered trucks and container
handling equipment to move containers within the facility is greatly reduced, thus reducing
emissions. The cranes have nearly doubled the capacity of the SIG facility, while reducing
environmental impacts and supporting economic growth of international commerce at the Port of
Seattle. In addition, the cranes and the new facility have increased facility throughput by nearly
30 percent. Finally, the cranes regenerate electricity into the grid every time they lower a load.
Pavement Reuse: Reuse of the existing asphalt and concrete pavement on the site saved cost to
the project and reduced the need to dispose of the material in a landfill. The project reduced the
need to import select fill by recycling approximately 6,500 cubic yards of pavement.
ACKNOWLEDGMENTS
In addition to David Evans and Associates, Inc., the design team included BERGER/ABAM
Engineers, Inc.; Northwest Utility Consultants, Elcon Associates, Inc.; and Landau Associates.
BNSF engineering and intermodal staff who contributed to the success of the project included
Danniel MacDonald, PE, Manager Engineering; Mike Powrie, PE, Project Engineer; and Sam
Phanekham, Manager Facility Development. Thanks to all of them.