Sustainability assessment of an urban rail system – The case of Hong Kong.

Urban rail system is a critical component of a smart and sustainable city. This paper applies the triple bottom line framework to assess Hong Kong's mass transit railway (MTR) performance. We collected data from MTR's annual reports and sustainability reports over the period 2008–2017. The data showed that MTR's urban rail system consumed 1,573 GW-hour (GWh) in 2017, up from 1,290 GWh in 2008. In terms of service capacity, MTR's urban rail system made 1.767 billion passenger-trips in 2017, up from 1.309 billon passenger-trips in 2008. The average passenger-km (pkm) travelled ranged from 10.4 to 11 km for city lines and from 28.4 to 29.5 km for airport express. The total pkm travelled by rail was 19.38 billion in 2017, up from 13.82 billion in 2008. Sustainability analysis showed that MTR's urban rail system had an efficiency of 0.076–0.093 kWh per pkm and produced 0.055–0.071 kg CO 2 -eq per pkm. Tobin's q value ranged from 0.638 to 1.043, suggesting that MTR's stock was undervalued in the capital market over the past decade. In terms of social performance, MTR's rail operations provided over 15 thousand jobs and handled 38.2 percent of public transport in 2017. • HK's urban rail handled 1.767 billion passenger-trips and consumed 1,573 GWh in 2017. • The total passenger-km travelled was 19.38 billion in 2017. • HK's urban rail system had an energy efficiency of 0.076–0.093 kWh per passenger-km. • HK's urban rail system emitted 0.055–0.071 kg CO 2 -eq per passenger-km. • The system's environmental and social performance has improved in the past decade. [ABSTRACT FROM AUTHOR]