were not included in this study). The eight stations were retrofitted with APGs in 2011. From July 2000 to December 2013, the MTR Corporation collected a surcharge of 10 cents from each Octopus-paying passenger to help pay for the installation of PSDs and APGs. Over HK$1.15 billion was collected in total. Platform screen doors were also installed on all platforms of the West Rail line (now part of the Tuen Ma line), then built by the Kowloon-Canton Railway Corporation (KCRC) before the MTR–KCR merger. The Ma On Shan line did not have gates upon opening even though it was built at the same time as the West Rail; they were eventually added from 2014 to 2017 prior to the opening of the first phase of the Tuen Ma line on 14 February 2020. The installation of platform screen doors in Hong Kong has been effective in reducing railway injuries and service disruptions. The longest set of platform screen doors in the world can be found in East Tsim Sha Tsui station, where it first served the when 12-car MLR trains were still in service. Following the completion of the Kowloon Southern Link and handing over of the station to the (now part of the Tuen Ma line), the subsequent reduction of train length from 12 to 7 cars caused many of the screen doors to be put out of service, although the trains were lengthened to eight cars in May 2018. The West Rail line (now part of Tuen Ma line), had all stations installed with APGs, and another constituent line of the Tuen Ma line, the Ma On Shan line, had its final APG installed enter service on 20 December 2017. The last non-tram/light rail stations in Hong Kong without platform screen doors or gates are all on the East Rail line, a former KCR line not part of the MTR APG retrofitting programmes. The KCR Corporation found it difficult to install APGs because of the wide curves of the platforms and large gaps of their platforms, especially in , , and station. However, these remaining thirteen stations are all being retrofitted by Kaba as part of the Sha Tin to Central Link project. The APGs are estimated to be at around high. Adding APGs to the East Rail Line platforms requires platform strengthening with rebars and brackets as the gates, combined with heavy winds, can greatly increase structural