The town of Hokutō 北投 is well-known for its hot springs, and appears to have been a popular tourist location during this era, as evidenced by the map in the 1935 publication of Taiwan tetsudo annai 台湾鉄道案内 (Guide to Travel on the Formosan Railways):
In the map, Hokutō is the station on the main line, and the branch line runs toward Shin-Hokutō at the upper right of the map.
A very short branch line from the main Tansui railroad runs up the hill to the center of Shin-Hokutō (New Hokutō) where there are many hot springs resorts, restaurants, and the like. The line was served by diesel locomotives of one or two cars, and was exclusively a passenger line.
This image from the 1935 map of Greater Taihoku shows the two towns and their position on the river.
This is an image of a wooden diesel passenger locomotive that was upgraded in the 1950s to a steel frame. It was likely cars like this that served the Shin-Hokutō branch line, and likely made local runs along the main lines as well.
The station at Hokutō, taken some time in the 1980s.
The terminal station for Shin-Hokutō is very distinctive. It was built in 1916 and was expanded with a wooden structure in 1937, the target year for the model railway.
This picture is of very low resolution, but appears to show a single-car passenger locomotive at the station. This was before the shelter depicted in the first picture was built.
A much later picture of the platform.
The current plan incorporates a dual-track station for Hokutō, with a sharp curve leading uphill toward the terminal in Shin-Hokutō. Some of the restaurants and pleasure quarters in the town will be depicted. There's a famous hot-springs resort that still stands today, if space allows I'll incorporate this historic building into the plan.