The state of Washington expects to seek bids in late summer or early fall for a project that will capture imaginations in this railroad towna 1,330-foot-long at-grade tunnel that will carry Burlington Northern Santa Fe Railways tracks underneath the long-awaited north-south freeway.


The state Department of Transportation is deep into design work on the tunnel, and though it doesnt have a cost estimate to release yet, it has designated $38.2 million in gas-tax money for the project, says Tom Brasch, assistant project engineer on the freeway, officially known as the North Spokane Corridor.


Because our project necessitated the need for the changes, basically DOT will cover all the costs, Brasch says.


The tunnel will carry BNSFs tracks at their current grade underneath the new freeway, which will cross the tracks between Piper and Hawthorne roads, just south of where the freeway will go over Market Street on a bridge thats already under construction. Not long after opening bids, DOT hopes to award a contract for constructing the tunnel, building and shaping the long incline that will carry the freeways northbound leg up and over the tunnel, and paving the northbound leg between Piper and where it will cross over Market, Brasch says. The freeway will come back to grade north of Parksmith.


The DOT should have a more firm schedule for the project four to six weeks from now, Brasch says. Just the northbound leg of the highway will be built at first, along with a bike path just to the east, because DOT only has enough money to build that part now.


One aspect of the job should be of particular interest to railroad buffs: At 54 feet wide, the tunnel will have room for a second BNSF track alongside the set of rails that carries freight trains through the Hillyard neighborhood now, Brasch says.


BNSF hasnt said, though, that it has definite plans to build a second track, he says.


How its been presented to us is that they have the right of way there for a second track, Brasch says. What theyre doing is theyre protecting their investment for the future. They dont want a choke point there.


The words railroad tunnel bring to mind the labor-intensive drilling, blasting, and rock clearing that crews did to claw their way through mountain ranges when the first intercontinental rail routes were built. This tunnel is a lot different. Rather than being dug through a mountain, it will be erected as a concrete arch structureand the incline that will carry the new roadway then will be built up over the tunnel with earth stockpiled after being extracted elsewhere along the North Spokane Corridor route. At first, the northbound leg will cover the tunnel, and later, the southbound leg will cover it, too.


We go over the track. Its much easier to do that than change the grade of the railroad, says Brasch.


The tunnel structure will be built with about 260 precast concrete arch sections, each of which will be 6 feet long. The sections will be assembled and connected to one another in a structure that will be high enough, at 28 1/2 feet from the top edge of the rails, for freight trains to chug through.


Each arch section will be made from two half-sections, each of which will weigh 21 tons. One to two cranes will lift the half-sections into place, setting their lower ends into footings. When two half-sections have been placed, they will be pinned at the top to secure them, Brasch says.


The tunnel will be built to accommodate the lean of the rail cars as they move along the curving track, Brasch says.


Theres a handful of issues that were working on with BN, Brasch says. They have some guidelines. They want to make sure that theyre covering their bases correctly.


DOT and BNSF still are working on tunnel lighting and ventilation issues, but have worked out track realignment and drainage issues, Brasch says. The contract requires the acquisition of crossing easements and airspace for footings from the railroad company, as well as construction and maintenance agreements, although the latter agreements will move forward when the other matters are resolved, he says.


Its too early to say when work will start on the project, Brasch says.


Right now, were charging hard to meet our late-summer schedule, he says, adding that the project could begin in the fall, and the early part of it would be similar to building a bridge.


You have to set the footings, Brasch says. While youre setting the footings, youre having your supplier cast the arches. By late winter, maybe by March, you could potentially be setting in the arches.


The project is expected to be done in the spring of 2009, and its possible the contractor will be able to work during part or all of the two winters that will come before then, he adds.


DOT intends to keep a commitment to the Legislature that motorists will be driving on part of the north-south freeway in the spring of 2009, and this contract, once its finished, would complete the drivable link from Francis to Farwell, Brasch says.


Contact Richard Ripley at (509) 344-1261 or via e-mail at editor@spokanejournal.com.