Express Freight Transportation Research Articles

Optimization of High-Speed Rail Express Transportation Plan Considering Products’ Variable Time Requirements

The global express market has expanded significantly in recent years. High-speed rail express freight transportation has been implemented between multiple cities in China, significantly improving transportation efficiency and effectively meeting demand. In this paper, an optimization model for HSR (high-speed railway) express transport plan is constructed using a space-time-state network, and an improved adaptive genetic algorithm is designed to solve the model. Reasonable transport schemes could be arranged for each cargo flow with the objective of maximizing operational revenue. The numerical experiment based on the Harbin–Dalian high-speed railway in China verifies the effectiveness and applicability of the proposed model. The results show that for HSR operators, appropriate transport strategies can be planned in terms of delivery priorities and transportation mode selection to make full use of the remaining capacity of HSR trains and increase operational revenue.

System Dynamic Model for Simulating Demand-Supply Interaction of Railway Express Freight System

Express freight transportation is a rich seam of profit for China railway, and railway express freight system is a complex system with multiple variables and nonlinear feedback loops. This paper presents a System Dynamic Model for simulating the interaction between demand and supply of railway express freight system in China. The model consists of three submodels including economic environment, demand, supply, and investment, and its validity is verified by running in Vensim DDS software using historical data. In the simulation of period 2000–2025, the three variables are taken as control variables including growth rate of the national economy, railway express freight rate, and investment in fixed railway assets. Three scenarios for each control variable are simulated, and their effects are analyzed to provide beneficial reference for regulating the demand-supply gap of railway express freight. The simulation demonstrated that raising freight rate, adding investment in fixed railway assets, and decelerating economic growth rate are all effective ways to shrink the demand-supply gap of railway express freight. The model can be used to forecast the transport demand of railway express freight and test the outcomes of demand-supply regulating measures.

An Operation Optimization for Express Freight Trains Based on Shipper Demands

The supreme goal of railway express freight transportation is to meet the various demands of shippers. This paper considers the optimization problem of the operation plan for express freight trains based on shipper demands, including transport volume, service frequency, and transit time. An integer programming model that takes maximum shipper demands as optimized objective is proposed to realize the assignment of trains to candidate paths. In this model, the number of marshalling cars for express freight train is set as a decision variable rather than a constant to better satisfy the demand characteristics. A heuristic solution algorithm based on genetic algorithm is then designed. Finally, a numerical case is applied to verify the feasibility of the model and the algorithm.