A paved greenway links the library and creekside parks, such as the Boulder Creek Fish Observatory (c. 1980), 28th and Arapahoe, which has viewing portholes built into a cement wall below creek level. Central Park, at the southeast corner of Broadway and Canyon Boulevard, contains the old number 30 locomotive (1898) of Boulder's narrow-gauge line, the “Switzerland Trail,” which served mountain towns west of the city from 1898 to 1919.