Railway alignment optimization should consider multiple environmental factors. Especially considering the changing climate, low-carbon design is crucial in alignment development. However, there is no reported study on alignment optimization considering life-cycle carbon emissions. To solve this problem, a model is proposed: (1) At the construction stage, carbon emissions generated by building material production and mechanical energy consumption are computed. (2) At the operation stage, train traction energy is converted into carbon emissions. (3) At the maintenance stage, carbon emissions generated by track replacement and structural maintenance are analyzed. (4) Moreover, the loss of carbon sink during a railway’s life is estimated. Next, the above factors are integrated by an annual attenuation analysis for obtaining the total carbon emissions. This model is then combined with a cost function to establish a bi-objective model and solved with a particle swarm algorithm. Finally, the model is successfully applied to a realistic railway case.

铁路线形优化应考虑多种环境因素。特别是考虑到不断变化的气候，低碳设计在路线发展中至关重要。然而，目前还没有关于考虑生命周期碳排放的对齐优化的研究报道。为了解决这个问题，提出了一个模型：（1）在施工阶段，计算建筑材料生产和机械能源消耗产生的碳排放量。(2) 在运营阶段，列车牵引能转化为碳排放。(3) 维修阶段，分析轨道更换和结构维修产生的碳排放。(4) 此外，估算了铁路全生命周期的碳汇损失。接下来，将上述因素通过年度衰减分析进行综合，得到总碳排放量。然后将该模型与成本函数结合建立双目标模型，并用粒子群算法求解。最后，该模型成功应用于实际的铁路案例。