The plan-and-construction of railway transportation facilities has been playing an increasingly important role in the development of metropolitan areas. Following the framework of railway transportation classification，this paper suggests two categories in the railway network of the Great Bay Area，namely “urban line” and “intercity line” from the perspective of geographical space and service audience. This paper also summaries the planning，construction，and completion of urban and intercity lines in three major areas. Since 2018，a series of changes have taken place in the railway transportation in the Great Bay Area. The construction of urban line has been affected by an official notice（File Number 52） issued by the State Council in 2018，and the process of the approving has consequently slowed down，pushing some cities to turn to other transportation means like trams. The main routes of the intercity line are scheduled to expand rapidly in the next two years，and a network will take shape soon. At present，there are still many problems in the development of railway transportation with respect to planning，construction，and operation organizations. However，all can be effectively mitigated and solved through integration planning，operational innovation，and convenient payment.