Abstract: In order to clarify the interaction mechanism between the flow and lines in railway system, the influence of train delay on wagon flow connection at technical stations was analyzed. By setting the minimum average residence time of transferring wagons as the optimization objective, a generalized wagon-flow organization model for technical stations was established with the constraints such as wagon flow connection. Based on this model, delay times were randomly generated following distribution rule of train arrival delay and added to train arrival time. Thus, a set of delaying trains was formed and input into the generalized wagon-flow organization model to conduct simulation calculation. In the different cases of train delay, taking the delay rate of departing train and total delay time as the indexes, the wagon flow connection results under the same operation were analyzed. The analysis results show that the effect of train delay for a single schedule period on wagon-flow connection at technical stations is uncertain. However, the effect of train delay for multiple schedule periods shows strong regularity though the different values of the number of wagons at stations, delay rate, total delay time, and train formation plan, etc., lead to different wagon-flow connection results. Finally, the necessity and feasibility of joint optimization of flow and lines was validated.