A comprehensive assessment framework for carbon emissions in urban rail transit systems

The carbon emissions of urban railway transit (URT) are crucial to assess sustainable effect of such systems. However, few studies were conducted in the lifecycle perspective of URT. Therefore, this study develops a comprehensive assessment framework to evaluate carbon emissions in URT systems, targeting sustainable performance optimization. The framework analyses four lifecycle phases: embodied emissions from material production and construction, rail traction energy consumption, station operational energy demands, and comprehensive carbon emissions factors. Through three selected case studies, the assessing certification suggests that the carbon emission-based environmental impacts of construction-related parameters and operation-related variables on environmental outcomes.