After the southbound train passes the Sanyi station and go through Sinwu Tea Garden around the Sun Yet-sen Freeway, it’ll turn right and then left to increase the hill-climbing distance to press onto the highest spot of the railway without letup. 

The big curve with 2.55% gradient is the most famous spot for photography on the Mountain Line. If one chooses to sit at the west side in the last few carriages of the train, he will be able to see the locomotive dragging the carriages behind. The train resembles a worm laboredly struggling uphill and forms a very interesting view. 

Later, the train will go into the first tunnel of the Mountain Line. This tunnel built up of bricks still carries its original appearance. With a length of 230 meters and a gradient of 2.6%, it is the most perpendicular section of the railway system in Taiwan. At times of rain, many trains actually have difficulty going uphill and need to add a supplementary locomotive to push the train upward to arrive the highest point, the Shengsing Train Station.