English: A figure explaining a method to construct double tracked line in steep summit section. Some part of the conventional single track line with steep slope is reused in the double tracked line by adding two slow grade lines. For both direction, uphill trains can use the slow grade line.
{{Information |Description={{en|A figure explaining a method to construct double tracked line in steep summit section. Some part of the conventional single track line with steep slope is reused in the double tracked line by adding two slow grade lines. Fo