By simulating the track irregularities with trigonometric series method,the train-bridge coupling vibration equations are established based on the combined modal of train formation and the bridge.

The author analyses and predicts the growth and developement trends of the passenger flow, holds that more trains put into running with the present train formation shall be the direct solution and a more effective way to enhance the transport capacity in Shanghai Metro Line 1.

By examining the test results of vibration for a few bridges, it is found that train formation has a strong effect on bridge vibration responses.

Based on the analysis of urban passenger flow, t he possibilities and problems of train classification in different operation per iods,the authors hold that in the near future,adopt the marshalling service shal l adopt the mode of half maximum classification,while in the far future,adopt se parate and group mode.

Based on the analysis of some important problems in metro designing, such as long-period prediction of passenger flow, passing capacity and fit train classification, the author holds that ticket price shall be the main item which restricts the metro flow, because to improve the passing capacity to forty pairs per-hour is only a future objective - "small train formation, high operation frequency".