The Chinese Eastern Railway (CER) is a really long train track that runs through the northeastern part of China. It was built a long time ago by two countries, Russia and China, who wanted to improve transportation in that area.
The CER starts in the city of Dalian and goes all the way to the city of Harbin. This train track is really special because it connects China to Russia. It also helped people in the northeastern part of China get their products to other parts of the country and the rest of the world.
The building of this railway wasn't easy. It took a long time and a lot of people had to work together to make it happen. The Russians did most of the building and management of the CER, but the Chinese government had some control too.
Eventually, the CER became controversial because the Russians started to use it to move their military around. This made some people in China worried that they were being controlled by the Russians. It also caused conflicts between China and Russia.
Today, the Chinese Eastern Railway still exists as an important transportation route, connecting China to Russia and helping people in the northeastern part of China move around and connect with other parts of the world.