animals moved from the old zoo, which remained in operation. The initial train service around the yet-unfinished new zoo grounds was suspended in mid-September 1958, not to resume until the zoo's opening in July 1959. A fundraising campaign was launched, to raise money to build an extension – outside the zoo grounds – through the woods of Washington Park and also to build a steam locomotive. It was decided to model the planned steam engine on a real one, a Baldwin 4-4-0 type, and construction began in the autumn, with plans to use it initially at the Oregon Centennial Exposition, scheduled to be held the following summer in North Portland (at the site of what is now the Portland Expo Center). The steam engine was named "Oregon", or alternatively "the Oregon". In the summer of 1959, the Portland Zoo Railway operated trains at two different sites. Nos. 1 and 2, the Oregon and the Zooliner, served a temporary railway line through the grounds of the Centennial Exposition, which lasted for about three months. The Zooliner entered service on the exposition's opening day, June 10, along with a second train hauled by a utilitarian diesel switcher locomotive temporarily filling in until the new steam locomotive, No. 1, was ready. The steam locomotive entered service on June 20, and it and the streamlined Zooliner proceeded to carry passengers daily at the exposition all summer. Meanwhile, the railroad at the zoo's then-new site in the West Hills remained closed while construction continued on the zoo itself, but reopened on the latter's opening day, July 3, 1959 (by which time most animals had been moved from the old zoo). For the next few months, the zoo line was served only by a train hauled by the locomotive that had been used during construction of that line. That locomotive (later becoming No. 5) was a diesel engine made to look like a steam locomotive, and the train was called the Circus Train. The engine and its cars have been modified several times since and are currently known as the Oregon Express. When the Centennial Exposition ended (on September 17, 1959), the two trains used there were moved to the new zoo line, although the steam locomotive did not enter service at the zoo until January 1960. The extension eastwards through the park to a new station near the Rose Gardens opened on May 28, 1960.