Jason Tweet takes long easy strides, landing each foot naturally on the oddly spaced railroad trusses as he begins leading a tour through the rusted beams of the Coos Bay Railroad Bridge.

A hollow bell reverberates as the entourage begins to pass over the green bay waters, announcing that the bridge is open for ships to pass.

"Are you sure that bridge will support all of you?" joked a man fishing for perch from a small boat anchored near the bridge.

"That's what we're here for," Tweet answered back.

The project manager for Madison, Wisc.,- based Osmose Engineering firm is gearing up for the longest portion of work on the dilapidated bridge, a job that will require replacing a large amount of rusted steel and that is estimated to take until mid-October. Osmose, one of the largest bridge rehabilitation companies in the nation, was contracted by the Oregon Department of Transportation to lead the way to the $6.7 million repair.

The company's success is vital to the South Coast and its dwindling industries, particularly the remaining mills that operate in Coos Bay and Coquille. For them, rail provides the most cost-effective way to transport logs, wood chips or other local commodities to the rest of the state.

In Coquille alone, at Roseburg Forest Products, approximately 350 jobs depend on the steel bridge. Company officials have told the bridge's owner, the Oregon International Port of Coos Bay, that the company would close down the operation without access to rail.

"Obviously, it's something we need to continue to work on," said port Commissioner Caddy McKeown. "We do have clients of the bridge that need this service."

Despite its rusted appearance, port officials say the bridge has not been weight restricted and loaded trains still pass the span - usually at night since the repairs began so that workers can operate without interruption. Martin Callery, the port's director of marketing and communications, credited the bridge's original engineering and the fact that the span was overbuilt when construction began in 1914 - capable of handling much more than ever has been required.

But after decades of sea water, salt, whipping winds and neglect, the bridge's disrepair is obvious.

Above the water, damage is clear to the eye. Crisscrossing beams are riddled with holes where orange rust has eaten into the silver paint. Some of the lateral beams no longer connect because the damage has become so extensive. In places, steel flakes off at the touch of a finger.

"We see bridges in this condition from time to time," Tweet said. "It's nothing out of the ordinary."

The underwater damage, though, isn't visible and was even more extensive than first thought several years ago, when the bridge was inspected by engineers to determine how much repairs would cost.

Scoured by decades of dredging, storms and tides, the concrete base of the piers that support the bridge became exposed to water and marine borers that began eating into the wooden pilings. The wood is meant to give flexibility and strength to the concrete, but exposed, it is a liability to the structure's integrity.

Osmose, which will handle the above-water steel work, subcontracted the underwater repairs to Coos Bay's West Coast Contractors. Owned by current Oregon International Port of Coos Bay President Dave Kronsteiner, West Coast Contractors was awarded the job before Kronsteiner was appointed to his position by Gov. Ted Kulongoski.

The company's repairs remain hidden by the green-tinted water, but after working 12-hour shifts, six days a week since November, crews have finished their portion of the work. The company will be demobilizing its crane and leave the site today.

Since beginning work on Nov. 11, West Coast Contractors removed large boulders surrounding the two central piers that support the swing span. Then, underwater scuba divers encircled the piers with sheet metal and filled the base, 56 feet by 20 feet, with new cement, pumping the concrete 1,700 feet to its final, underwater destination.

The local company installed fenders made of plastic on the inside piers of the swing span. Workers also replaced four steel bents - part of the stabilizing framing of the bridge on the north and south approaches.

West Coast Contractors completed the job in the past week. The in-water work period, which ended at the end of February, was extended to allow the crews to finish the remaining portions of their job.

"As a marine contractor, they're very good at what they do," Tweet said. "I've learned a lot of different things from them."

Now, the majority of Tweet's portion of the work is just beginning. Osmose is shipping work crews from Vermont to handle their portion of the job, which will focus on rebuilding much of the rusted and nonexistent steel laterals that frame the bridge.

Osmose will face its own challenges to get the job done right.

Because it was built in 1914, the bridge is subject to historic preservation guidelines that require the span not be altered from its original state.

"It has to be replaced in like kind," said Hara Miller, a project inspector with Jacobs Civil, the engineering firm hired by the port to oversee the repairs. "American Bridge is having to fabricate a lot of the pieces."

Recently settled near Reedsport, the Pennsylvania-based company is doing the majority of the steel work for the bridge, Miller said.

While much of the material is being custom made, some changes are inevitable. Rather than riveting the steel pieces, for example, Osmose will use large bolts to hold the beams in place.

Tweet said having to follow historic preservation guidelines may add some to the cost of the rehabilitation but having American Bridge about 20 miles away from the work site also lowers those costs.

When the company's repairs are finally completed in October, it will put an end to approximately a decade of work by port officials to finance the work.

The port finalized the $1 purchase of the rail bridge from Union Pacific in 2000, but officials began looking for funding to repair it in the early 1990s.

With the help of Rep. Peter DeFazio, D-Ore., the port received a $5.5 million grant to help pay for repairs. In addition, the state awarded the port a nearly $1 million grant and a loan of approximately $250,000. The Coos County Urban Renewal Agency also contributed some funding.

To help repay the state loan and to build up funding to match any future grants, the port began issuing a tariff on all loaded rail cars that pass the bridge. The tariff, which went into effect Jan. 1, charges $5 per car on all low commodity rail cars, such as those carrying raw logs or wood chips, and $28 per car on all high-value items. Union Pacific has agreed to pay $8 of the tariff on the high-value items.

Callery said the port estimates it can generate between $50,000 and $70,000 per year through the tariff.

Port officials believe that tariff is integral to finding funding for future repairs and for maintaining the bridge in the future so that it will no longer become dilapidated.

In 2003, despite funding contributions from numerous sources, the port discovered it couldn't afford the full repair, which would extend the life of the bridge by up to 40 years, so it chose a partial fix focusing on the swing span first. Once repairs are completed, the span will have a new life expectancy that ranges decades but the port still has to hurry to find funding for the remaining repairs.

"It gives us five to seven years to come up with funding for other ... parts of the bridge," said Callery.

With phase one of the project focused so extensively on the swing span, future repairs will target the remaining 12 spans of the bridge. In 2003, a total fix to the bridge was estimated to cost between $13 million to $14 million.

Touring the bridge for the first time over the weekend, McKeown said she was prepared for the obvious damage and wasn't surprised by its condition. But McKeown said seeing the bridge in such disrepair also strengthens her resolve to find more funding for its restoration.

"This is an important project and I'm pleased we were able to secure the funding for phase 1," she said. "What it does is, it energizes you to find funding for phase 2."