Figures (6)  Tables (2)

    • Figure 1. 

      Key elements of the net GHG impact of urban rail transit systems.

    • Figure 2. 

      Urban rail transit life cycle process.

    • Figure 3. 

      Research boundary of life cycle carbon emission measurement for urban rail transit.

    • Figure 4. 

      Case station intelligent control platform display interface.

    • Figure 5. 

      Architecture of building equipment monitoring and energy management system of the case station.

    • Figure 6. 

      Interface of building equipment monitoring and energy management system of the case station.

    • ContinentCountry/regionMetro mileage (km)Light rail mileage (km)Tram (km)Total (km)
      AsiaChina8206.48422.51563.639192.62
      EuropeGermany403.10−3537.493940.59
      North AmericaThe United States1384.101316.01353.323053.43
      EuropeRussia640.2058.701369.202068.10
      EuropeUkraine114.0621.001209.601344.66
      EuropeFrance362.3018.40861.101241.80
      AsiaJapan791.20108.80220.451120.45
      EuropePoland35.5020.10970.001025.60
      EuropeSpain510.00146.12340.79996.91
      AsiaKorea837.4488.31−925.75
      EuropeThe United Kingdom450.5099.50229.60779.60
      AsiaIndia709.49−28.00737.49
      EuropeItaly221.7027.70361.30610.70

      Table 1. 

      Total length of urban rail transit operation lines around the world in 2021.

    • Country/
      region      		CityType of urban
      rail transit      		Research
      boundary      		SummaryReference
      ChinaBeijingComprehensiveOperation and maintenanceNo carbon emission by default for power generation methods other than thermal power[88]
      ChinaHefeiMetroLCAThe digital twin system was introduced to assist in LCA; there are limitations in data interoperability between different models of the system[97]
      IndiaDelhiMetroOperation and maintenanceThe impact of transport mode shift due to the introduction of the metro on carbon emission is considered[95]
      ChinaBaojiComprehensiveOperation and maintenanceDeveloped a passenger demand-based carbon emission model[100]
      AustriaViennaMetroLCAIgnoring carbon emission from maintenance, dismantling, and recycling phases[32]
      BrazilRio de JaneiroMetroLCAThe GHG emissions compensation period of the urban rail transit system was analyzed[78]
      United StatesLos AngelesLight RailLCATwo different LCA frameworks are used[60]
      United StatesPhoenixLight RailLCADeveloped an integrated transportation and land use LCA framework[79]
      ChinaBeijingMetroConstruction and buildingA quota-based GHG emissions quantification model for metro station construction is proposed[62]
      CanadaTorontoStreetcarOperation and maintenanceStudy of GHG emissions from the construction and reconstruction of the Spadina streetcar route[68]
      United KingdomLondonMetroOperation and maintenanceAnalyzed the impact of changes in passenger travel behavior on GHG emissions from metro[70]
      United StatesNew JerseyCommuter railConstruction and buildingDifferent material inputs were evaluated during the construction of the railroad project[75]
      ItalyRomeMetroLCAThe use of data sourced from metro operators reduces the uncertainty of the results[80]
      TurkeyKayseriLight RailLCAIntegrating environmental, economic, and social factors with the LCA approach[83]

      Table 2. 

      GHG emissions measurement model of urban rail transit in literature.