When the zoo was renamed again in 1998, as the Oregon Zoo, the railway was not renamed. The line also served the Oregon Museum of Science and Industry from 1958 to 1992 while that museum was located near the zoo. A suspension of service forecast to last at least through summer 2014 was due to begin on September 23, 2013, to allow construction of a new elephant exhibit area and changes to the railway's route within and near the zoo grounds. On November 22, 2014, operations resumed on the new Zoo Loop line. The railway was listed on the National Register of Historic Places in 2020. The 35-40 minute round-trip Washington Park route runs on weekends from mid-April until Memorial Day and then daily through Labor Day. (However, service along this route has been suspended for an undetermined time, as repairs are needed on retaining walls along the track.) This run goes through the woods of Washington Park and the grounds of the Oregon Zoo. (Few animals are seen from the train.) The Zoo station is near the zoo entrance (). The Washington Park station is a short walk from the International Rose Test Garden () and Portland Japanese Garden. The line includes a section of 4.5-percent grade. In the off-season, weather and business permitting, the 10-12 minute Zoo Loop trip runs. This run goes through the Oregon Zoo grounds only. The Washington Park trips that operate during spring and summer months also cover this section. The Zoo Loop is mostly a one-way loop, whereas the two-way 2-mile line through Washington Park is single-track but equipped with a few sidings to allow trains running in opposite directions to pass. This allows up to three trains to be in operation at once. As of 2010, Washington Park and Zoo Railway has three trains in normal operation: The "Zooliner", 4-4-0 No. 1 "Oregon" (original steam train), and "Oregon Express". Two of them (the "Zooliner", and 4-4-0 No. 1, "Oregon") are scale replicas of real trains. In addition, there are two small switcher locomotives that are used for non-passenger purposes. Most regular service, including all non-holiday weekday service, uses only two diesel trains. The steam train operates on only a few weekends per year and for special events. In the 1980s, two of the three trains were equipped with wheelchair lifts to allow mobility-impaired persons to board the train, and in 2005 these lifts were upgraded so as to better accommodate heavier electric wheelchairs.