3-line construction has a special historical background and mission. A major strategic decision made by the country in the mid-1960s was a major strategic adjustment to gradually change my country's productivity layout in order to strengthen combat readiness, and the focus of construction was on , southwest and northwest.

Located in the southwest region of . Chongqing has become a key area in the construction of the third line in the country due to its strong industrial strength, superior geographical location and rich natural resources. In the mountains around Chongqing, there are many former sites of third-tier military factories hidden. Although they have withdrawn from the stage of history, the precious wealth left by the "third-tier construction" has still had a far-reaching impact.

,000 yuan Jinlin Machinery Factory is located in the valley of Haikong Village in the southwest of Conglin Town . It is only close to Jinfoshan Scenic Area and 130 kilometers away from Chongqing city. Walk up the winding mountain road, and in the rarely visited mountain canyon, some old green and red brick buildings are looming in the dense jungle. This is the old site of the abandoned Jinlin Machinery Factory.

Jinlin Machinery Factory, also known as Factory 157, is a large arsenal with the third line construction layout in Chongqing. It mainly produces artillery . The products of this factory were used in self-defense counterattack against Vietnam and the Iraq War, making significant contributions to the development of the national defense cause. This was also the former site of the National Government's Second Aircraft Manufacturing Factory. In 1935, the National Government cooperated with Italy to establish the "China-Italy Aircraft Manufacturing Factory", and later moved here due to war. After

, in the third line construction period, based on the principle of "backing, dispersing, and concealing", this place was re-activated to build Jinlin Machinery Factory. Factory 157 broke ground in 1965 and was put into use in just two years to produce large-caliber howitzers. Thousands of factory workers and families left their hometowns to the remote mountainous areas in the southwest, and on this hot land, they exude their passion and write a new life. Although the factory is in the deep mountains, the life of employees is not a problem. Hospitals, children's schools, cinemas, cultural palaces, lighting stadiums, nurseries, libraries, auditoriums, police stations, guesthouses, and TV stations are all available. Every morning at 6:30, the broadcaster turned on the wake-up number on the speaker, people listened to the news and ate breakfast, and went to the workshop to work at 8:00.

At that time, thousands of troops entered the third-tier tier, but the welfare benefits of third-tier factories were higher than those of state-owned enterprises in cities. Every year during the Spring Festival, except for buying tobacco, alcohol and tea, you basically don’t need to buy other New Year’s goods. The factory allocates the plan. The factory's cultural activities are also rich and colorful, and various performances are often held. There are several movies every week. Before the TV was popular, the factory club had color TVs.

Entering the 1990s, under the impact of the wave of the planned economy transforming into market economy . Although it has a group of excellent technical talents and a large number of excellent equipment, the Jinlin Factory has begun to suffer losses due to information and inconvenient transportation. In addition, the location is relatively remote and gradually moved outward in the late 1990s. In 2003, it moved to Chengdu's Pengzhou as a whole.

After that, the huge factory area was neglected, and residential buildings were abandoned, with sparsely populated and particularly desolate. Some of the dormitories in the factory tray were idle and abandoned, some were lived in or fed to poultry and livestock by farmers. There were slogans from the 1970s on the exterior walls of the old factory.

The glory of the past is hard to say goodbye. From time to time, the former employees and children of Jinlin Factory come here to search for the past time. It is the 20 years of glorious years and passionate memories of youth. The prosperous third-tier factory of has deeply affected the development process of New China and is enough to be recorded in history forever.