The trains run on Hakodate line between Sapporo and Sōen.
The line run originally between Sōen (Sapporo) and Ishikari-Numata station on the Rumoi Hon Line. The section beyond Shin-Totsukawa was closed in 1972. However, the line name still reminds of the old destination as "Sasshō" is made up of the inital kanji signs in Sapporo and Numata (alternative reading of the "numa"-kanji is "shō").
From Sapporo to Ainosatokōen the trains run every 20 minutes. But the further up the line, the fewer trains.
There are no through trains from end to end, a change is required in Ishikari-Tōbetsu.
Shin-Totsukawa station is about 3 km from Takikawa station on Hakodate and Nemuro lines.