Optimization for train plan of urban rail transit based on hybrid train formation

In order to meet the fluctuation of passenger flow, a multi-objective optimization modal for train plan of urban rail transit based on hybrid train formation is established, which is aimed to minimize the passengers'waiting time and operator's cost. The constraints are transport supply, policy headway and fleet size. And a two-phase mathematical programming algorithm is also proposed. At last, the validation of the proposed model and the algorithm has been tested with an urban rail transit line in China. The results show that compared with the traditional train plan of single train formation, the train plan based on hybrid train formation can reduce the waiting time of passengers and the cost of operation by 17% and 27%, but increase the total train-hours by 20%. When the threshold ratio of peak demand to off-peak demand is more than 1.48, the train plan of hybrid train formation is preferable. Copyright © 2016 by Science Press.