TriMet will announce the name of Portland's first Willamette River bridge in four decades on Wednesday.

What will it be: Abigail Scott Duniway Bridge, Cascadia Crossing, Tillicum Crossing and Wy'East Bridge?

The 1,720-foot transit bridge between the Marquam and Ross Island bridges is the cornerstone of the $1.5 billion MAX Orange Line from Portland to Milwaukie, which is set to open in September 2015. It's the first multi-modal bridge in the U.S. to carry light rail and streetcar trains, buses, bikes and pedestrians, but no private vehicles, TriMet says.

A 10-member naming committee led by local historian Chet Orloff was charged with coming up with the finalists out of 9,500 public suggestions.

The naming committee also settled on the final name. The naming ceremony will take place at 10 a.m. on the east end of the bridge, outside OMSI.

Here are the stories behind the four name finalists:

Abigail Scott Duniway Bridge:

Cascadia Crossing:

Tillicum Crossing:

Wy'east Bridge:

-- Joseph Rose