The agency that operates the light rail network, as well as the area's extensive bus system, and also a commuter rail line on the Westside, is formally the Tri-County Metropolitan Transportation District of Oregon.  It is customarily known as TriMet.  Light rail consists of four lines, collectively called Portland MAX.  The second part of that title is an approximate acronym for "Metropolitan Area Express."  Its selection as the nickname for light rail was the result of public voting done while the initial part of the system was being built in the 1980s.

An area that encompasses downtown and a strip through the Rose Quarter and Lloyd District east of the Willamette River, is free at all times for MAX (and Portland Streetcar) riders whose entire trip is within the boundaries.  That "Free Rail Zone" is treated in this first section of these pages.  And the material is further divided into four segments, which cover, sequentially, the original route in downtown; Steel Bridge; the free territory east of the Willamette River; and then back to center city, touring the much newer Portland Mall route. 

Further sections leave the free zone, and cover, in order, Eastside MAX out to Gresham; the Westside line to Hillsboro; the Red Line to the Airport (beyond where it leaves the Blue Line); the Yellow Line to Expo Center; and the Green Line to Clackamas Town Center, also after it leaves the Blue.

The view on this page shows a Red Line train just off Steel Bridge, east of the Willamette River.  This model is the newest of the four models acquired by MAX over the years.  The system fleet consists of 126 light rail vehicles. 

The short and slow stretch on the bridge and its approaches is the only trackage common to all four MAX lines.  The rails that branch to and from the right carry the Yellow Line.