It should have been a celebration for new $181 million train route. What went wrong?

They were the first passengers to use a $181 million railroad project that paralleled Interstate 5. It should have been a celebration Monday for everyone on board Amtrak Cascades 501.

Instead, it became a disastrous derailment that has killed three people and hurt nearly everyone on board the train, along with several auto passengers on the freeway below.

How could the first run of a project 10 years in the making go so horribly wrong? Officials will be asking that question in the days, weeks and months to come.

“Obviously it could be an operator error, it could be an obstruction on the line itself or it could be a safety issue where the track was not able to handle the speed,” said state Rep. Jake Fey, D-Tacoma, the vice chairman of the House Transportation Committee. “All of those things are bad.

“You want to be sure when you build new projects like this that they’re going to be safe. This is not good for encouraging passenger traffic on Amtrak from Portland to Tacoma.”

Amtrak operates the Cascades regional trains for the Washington and Oregon departments of transportation. The trains run between Eugene, Oregon, and Seattle. Another route goes from Seattle to Vancouver, British Columbia.

On Sunday evening, Amtrak ran its last passenger trains along the old route that followed Puget Sound’s shoreline.

On Monday morning, a new Tacoma train station opened at Freighthouse Square and Cascades train No. 501 left about 7 a.m. on its way to Olympia using the new, inland route.

It never made it to the capital, derailing about a mile from where it would have rejoined the old route near the Billy Frank Jr. Nisqually National Wildlife Refuge.

A total of 14 Cascades trains were intended to use the new passenger route each day. In addition, Amtrak’s signature West Coast train, the Coast Starlight, was to use the route twice daily, going south to Los Angeles and north to Seattle.

Transportation officials have long wanted to bypass the scenic route along Puget Sound for two main reasons: It would cut 10 minutes of travel time off the Tacoma to Olympia route, and it would ease congestion on the old route.

The old, shoreline route was intended to be used only by freight trains operated by BNSF Railway, starting Monday.

That route was the scene of another Amtrak Cascades derailment July 2 that injured some of the 267 passengers on board. That accident also occurred near a train bridge. The cause was attributed to excessive speed and outdated equipment.

The Point Defiance Bypass project was seven years in the making with planning and design before then.

The tracks are owned by Sound Transit. Before the project began they were owned by BNSF and used for the occasional freight train as well as military transport, according to a statement from Amtrak.

The new Amtrak route uses the same tracks Sound Transit Sounder trains use on their way to Lakewood from Tacoma. That route splits off from the mainline where Interstate 5 crosses the Puyallup River, east of Freighthouse Square.

From Lakewood, the new route takes only Amtrak trains south along Interstate 5 on completely rebuilt rails, track bed and crossings. However, the trestle and concrete abutments where the derailment occurred were decades old.

After crossing that bridge the route then connects with BNSF Railway’s main line just north of Nisqually.

For more than 100 years, passenger and freight trains have traveled along Tacoma’s waterfront, along Puget Sound and then headed inland just north of Nisqually.

Those trains used a train bridge over Interstate 5 about 4,000 feet south of the bridge that was the scene of Monday’s disaster. The two routes meet up and become one just south of there.

Amtrak planned to run its trains up to 79 miles per hour. It’s unknown how fast the derailed train was moving Monday.

Officials have been testing the new route but details on how extensive those tests have been were not available Monday.

As of late Monday morning, Amtrak Cascades and Starlight trains were once again using the shore route.

Craig Sailor: 253-597-8541, @crsailor

Related stories from Tacoma News Tribune