考虑碳排放成本的铁路集装箱快递班列开行方案

针对我国目前快递公路运输方式占比过高，而导致的道路交通需求过大、运输成本、碳排放过高等问题，研究了“双碳”目标下铁路集装箱快递班列方案。考虑运输距离、快递量、快递网点数量、物流产业占GDP比重等因素，运用熵权法确定集装箱快递班列始发站和到达站。根据公路直达运输和调运至铁路车站2种形式，构建包括始发站、调运站和到达站的铁路集装箱快递班列运输网络。为确定集装箱快递运输直达方案、调运方案及采用的运输方式，建立了铁路集装箱快递班列开行方案的整数规划模型。为确定集装箱快递班列合理的列车编组数量及铁路经济运距，该模型以运输成本、调运成本和碳排放成本最小为目标，不仅综合了快递运量、时间约束以及列车开行条件等因素，而且考虑了快递货物的调运流程。此外，该模型还引入了碳排放系数、碳交易价格等要素，以计算碳排放成本。以长三角地区快递货流集散为例进行了实证分析，结果表明：铁路集装箱快递班列开行方案以直达运输为主，调运方式为辅；运输方式按照载货量及铁路经济运距划分铁路运输为主，公路运输为辅；列车合理编组范围为25~40辆，且列车编组数量过高和过低均不具有优势；设定铁路运输速度120 km/h的条件下，铁路经济运距以400 km为宜；科学设计时间窗约束亦能优化铁路集装箱快递班列开行方案。与现行公路运输相比，本研究所得方案的运输成本和碳排放成本均明显降低，运输时效性亦能够得到保证。

An Operation Scheme for Regular Train Services for Transporting Containers Considering Carbon Emission Cost

Currently, a high proportion of the express delivery service in China is carried out through road transportation, which has led to the following issues, including an excessive traffic demand, a high transportation cost, and high carbon emission. Aiming to address these issues, an operation scheme for regular train services for transporting containers (RTS-TC) under"dual carbon"goals is studied. Considering the factors such as transportation distance, express delivery volume, the number of express delivery outlets, and the contribution of the logistics industry to overall GDP, an entropy weighting method is employed to determine the origin and destination stations for RTS-TC. Based on two types of transportation, highway transit only and transfer to railway stations, a transportation network for RTS-CT is developed, including the origins, transfers, and arrival stations. To determine the scheme for direct transit, the transfer scheme, and the corresponding transportation mode, an integer programming model is developed for the operation scheme of RTS-TC. To determine the reasonable number of RTS-TC formations and the railway economic distance, the model minimizes the transportation costs, transfer costs, and carbon emission costs. The optimization considers the factors such as the express delivery volume, time constraints, and train operation conditions, as well as the transfer process of express goods. Additionally, the model incorporates elements such as the carbon emission coefficient and carbon trading prices to calculate the carbon emission costs. A case study is conducted using the express freight flow distribution in the Yangtze River Delta region. The results show that the operation scheme for RTS-TC primarily adopts the mode of direct transportation with the transfer mode as a secondary option. According to the cargo capacity and railway economic distance, the railway transportation is preferred over the road transportation. The reasonable number of wagons for RTS-TC formations is between 25 and 40, as an excessively large or small number of RTS-TC formations is not advantageous. Under the condition of a railway speed of 120 km/h, a railway economic distance of 400 km is considered optimal. The constraint of a scientifically designed time window can also further optimize the operation scheme for RTS-TC. Compared to the current road transportation, the proposed schemes in this research significantly reduce the transportation costs and the carbon emission costs, while ensuring the transportation timeliness.