More than 30,000 Portland-area residents showed their enthusiasm for light rail Saturday by taking advantage of free rides on the MAX Green Line that connects Portland State University and Clackamas Town Center. By Monday — the new line’s second full day of official operation — an estimated 17,800 riders paid to board the new MAX line and journey to work, school, health care or shopping. That number represents about 70 percent of the total daily trips expected on the Green Line after a year of operation. Clearly, an impressive number of Portland-area residents believe taking MAX is a desirable way to move about — whether it is in downtown Portland, to Gresham, Beaverton or Hillsboro, to Portland International Airport, north along Interstate Avenue or now south into Clackamas County. Light rail does not replace the automobile, nor bus service within a community. But it is an effective and affordable commuting tool — and a regional transportation and economic-development success story worth applauding.