Objective With the growing global concern about climate change, carbon emissions from the transportation sector have become a major research focus. As an important part of the urban comprehensive transportation system, the carbon emissions during the construction phase of suburban railways cannot be ignored.

Method This paper constructs a theoretical framework for analyzing the carbon emissions throughout the life-cycle of the construction phase of suburban railways, clarifies the scope of carbon emission measurement, conducts an in-depth analysis of carbon emissions in the building materials production and transportation phase and the construction phase, and establishes corresponding measurement models. A typical case study of the suburban railway in Jiaxing City is carried out.

Result & Conclusion  The research results show that the total carbon emissions of the three underground stations on the Fengnan Line amount to 301 900 tons of CO₂, accounting for 59% of the carbon emissions of all stations on the line, which is 1.35 times the carbon emissions of all five elevated stations on the Xitang Line. Through the design of 62.6% elevated sections on the Fengnan Line, the carbon emissions per unit length are 50% lower than those of the Xitang Line. For every 10% increase in the proportion of the elevated section on the Fengnan Line, the carbon emissions per unit length decrease by 1 500 tons of CO₂/km. The total carbon emissions per unit length of the two lines are 23 100 and 27 800 tons of CO₂/km respectively, both lower than the domestic average of 41 500 tons of CO₂/km for rail transit. The above results verify the advancement of the construction model of the suburban railway in Jiaxing, providing theoretical support and technical guidance for the low-carbon development of suburban railway construction.