High speed railway is a complicated and enormous system. Beijing-Tianjin inter-city railway is the first high speed railway that has started commercial operation in China. There are significant innovations made on key technologies and four challenging issues including system design and integration, high track regularity and stability, high safety and riding comfort, reliable operational control and high efficiency. China Railways experienced three years to build Beijing-Tianjin inter-city railway. The operational performances of Beijing-Tianjin inter-city railway showed that the whole technology is ranking at the leading position in the world. The technologies are convincing exemplary demonstration and will be applied to build the high speed railway network in the future.