After the southbound train travels slowly to enter Shengsing Train Station, it can finally pass by Kaitian Tunnel with a fair speed to get to No.167 Signaling Station for train looping. All of a sudden, it arrives the highest iron bridge (33 meters) in Taiwan. This iron bridge was built after the disastrous Taichung earthquake in 1935. Remains of brick-built bridge structure can be seen at the east of the iron bridge. It is the most famous attraction on the old Mountain Line. 
The old bridge was built 90 years ago. The body of the bridge was constructed section by section using bricks and steel beams. The bridge across the valley of the Longteng Stream, a branch of Jingshan River, formed a grandeur view. However, it was damaged badly in the 1935 earthquake that it was impossible to be repaired. 
At present, fragments of bridge abutments can still be seen. Looking toward the new iron bridge from the remains or the view of Tung flowers all over the mountain besides the remains are both great spots for photograph. 

On 21 September 1999, the site was seriously damaged again by earthquake and the fifth abutment counting from the north was broken for the second time. It thus becomes the living witness that has gone through two major earthquakes in Taiwan. 
The Council for Cultural Affairs commissioned the Construction and Planning Agency of Ministry of the Interior to establish a memorial for the 921 Earthquake. Besides, the Sanyi town administration is also urging the conservation works for historical sites. This site and the Shengsing Train Station are now the two hottest tourist attractions on the old Mountain Line.