本文阐述了共同基金得定义、特点及其发展的历史和趋势，分析了共同基金的风险及收益，提出设立共同基金的现实意义，以及尽快建立铁路投资基金的建议。

The paper describes the definition, specialties and the history and developing tendency of the joint fund. The risks and profits of the joint fund are analyzed. The practical meanings for establishing the joint fund are proposed. Finally, the paper proposes that the railway investment funds should be established as soon as possible.