Osaka Monorail Saito Line

The line was built as an access route for the International Cultural Park City (国際文化公園都市), a large planned new town in the hills of northern Ibaraki marketed under the name Saito. An extension of the Hankyu Senri Line had originally been considered to serve the development, but a monorail was chosen instead in light of the projected population. From Bampaku-kinen-kōen the route crosses the Chūgoku Expressway and the Osaka Central Loop road on viaduct, curves halfway around the eastern side of the Expo Commemoration Park, and runs north past Handai-byōin-mae toward the new town.

The first section, from Bampaku-kinen-kōen to Handai-byōin-mae, opened on 1 October 1998. This stretch was brought into service ahead of the rest of the line at the request of Osaka University's medical school and its attached university hospital, and the two stations on it, Handai-byōin-mae and Kōen-higashiguchi, share the standardised station-building form used on the Main Line.

Work on the remaining section, from Handai-byōin-mae onward to Saito-nishi, began in 2002. It opened on 19 March 2007, completing the line at its present 6.8-kilometre length and five stations. The two stations added on this stretch, Toyokawa and Saito-nishi, were each given their own distinct architectural design rather than the Main Line house style.

Like the rest of the network, the Saito Line was caught up in the magnitude-6.1 earthquake that struck northern Osaka Prefecture on 18 June 2018, which suspended the whole line. Service was restored in stages: the Bampaku-kinen-kōen–Handai-byōin-mae section reopened from the first train on 22 June and the Handai-byōin-mae–Saito-nishi section from 13:00 the same day. On 24 June the line was halted again from the first train after a vehicle was found with a component at risk of falling, before service resumed.

On 1 June 2020 the operating company changed its corporate name from Osaka High-Speed Railway Co., Ltd. to Osaka Monorail Co., Ltd., the trading name it had long used. The change applied to the operator as a whole rather than to the Saito Line specifically, but it brought the company's formal title into line with the brand passengers already knew.

The Saito Line was once intended to grow further. A continuation eastward from Saito-nishi, through a provisional Chūbu station to a provisional Higashi-Center station, was planned to follow the new town's development. But after the eastern district's plan was changed from a residential area to an industrial estate — cutting its projected population sharply — Osaka Prefecture decided on 27 January 2017 to abandon the extension as unprofitable. The operator applied in January 2019 to abolish the unbuilt eastern tramway segment, and the abolition was approved on 19 March 2019, leaving Saito-nishi as the line's permanent terminus.

• 19981 October: the first section, Bampaku-kinen-kōen–Handai-byōin-mae, opens, brought forward at the request of Osaka University's medical school and university hospital.
• 2002Construction begins on the remaining Handai-byōin-mae–Saito-nishi section.
• 200719 March: the Handai-byōin-mae–Saito-nishi section opens, completing the 6.8 km, five-station line to Saito-nishi.
• 201727 January: Osaka Prefecture decides to abandon the planned extension east of Saito-nishi as unprofitable after the eastern district's zoning shifts from residential to industrial.
• 201818 June: the magnitude-6.1 northern Osaka Prefecture earthquake suspends the entire line.
• 201822 June: service resumes — Bampaku-kinen-kōen–Handai-byōin-mae from the first train, and Handai-byōin-mae–Saito-nishi from 13:00.
• 201824 June: the line is halted again from the first train after a vehicle is found with a component at risk of falling, before service later resumes.
• 201919 March: the abolition of the unbuilt tramway segment east of Saito-nishi is approved, formally ending the extension plan.
• 20201 June: the operating company changes its corporate name from Osaka High-Speed Railway Co., Ltd. to Osaka Monorail Co., Ltd.