LCQ2: MTR South Island Line
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Question:
The MTR South Island Line (SIL) was commissioned on December 28 last year. However, a power remote control device at the Wong Chuk Hang Depot malfunctioned right on the following day, affecting the power supply of five railway stations along SIL. On the 14th of last month, South Horizons Station of SIL was closed for four hours due to serious flooding. Some members of the public have relayed to me that the aforesaid incidents have caused inconvenience to them and aroused concerns over the ability of the MTR Corporation Limited (MTRCL) in handling unexpected incidents inside railway stations. In this connection, will the Government inform this Council:
(1) as the Water Supplies Department has indicated that the aforesaid flooding incident was caused by leakage of water from a cracked fresh water main near South Horizons Station following its dislocation due to loosened support, and that the water main had been relocated during the time when the works of SIL were carried out, whether the authorities know the outcome of the investigation of the incident carried out by MTRCL, including whether the structure of the railway station has been affected;
(2) whether the authorities know if MTRCL has, in the light of the aforesaid flooding incident, examined the structural conditions of the water mains near the various railway stations along SIL, and re-examined the water main alignments near the various railway stations under construction, so as to prevent the reoccurrence of flooding incidents in railway stations; given that flooding inside railway stations can cause electricity leakages, thereby endangering the safety of railway staff and passengers, whether the authorities know if MTRCL has formulated safety guidelines for handling flooding incidents inside railway stations; and
(3) given that as SIL is plied by unmanned trains and covers the Nam Fung Tunnel which is as long as 3.2 km, MTR staff can only provide support at the next station should an unexpected incident occur in a train passing through the tunnel, whether the authorities know if MTRCL has formulated contingency plans for handling unexpected incidents that occur in trains passing through tunnels along the various railway lines, and whether MTRCL will conduct the relevant drills?
Reply:
President,
After the commissioning of the South Island Line (SIL) on December 28, 2016, it on the whole operates smoothly. The MTRCL already reported in detail the power outage incident on December 29, 2016 to the Subcommittee on Matters relating to Railways on January 17, 2017, and it would not be covered here.
For the question raised by Hon Kwok, I reply as follows:
(1) After the flooding incident at South Horizons Station at the night of February 14 this year, the MTRCL carried out inspection immediately and found that the connection of a fresh water pipe, of about 250mm (about 10 inches) in diameter and outside the station, was loosened. Fresh water was ejected and damaged part of the roof of Entrance/Exit B constructed by fire resistance board. Water then flowed into the concourse from the damaged roof. The MTRCL sought assistance from the Water Supplies Department (WSD) immediately and the Department fixed and strengthened the supports of the pipe shortly that night. After confirming the structural safety of the station was not affected, the MTRCL resumed the services of the Station at around 12.25am the next day. It is confirmed that the water pipe concerned was reprovisioned when constructing the SIL (East).
(2) In general, MTR underground stations buried in soil or rock are constructed using concrete structure and with waterproof layer to prevent ingress of water into stations. Nevertheless, as Entrance/Exit B is protected by the structure of the existing underground void and restricted by the space of that void, its design is rather special, and fire resistance boards are used for constructing its roof (the design of Entrance/Exit B is at Annex). After the incident, the MTRCL has reviewed the station design and alignments of nearby underground pipes of the SIL and other stations under construction, and confirmed that their designs are different from that of the Entrance/Exit B of South Horizons Station. The MTRCL has been investigating this flooding incident in depth with the Highways Department and reviewing the other utilities within the void that is accommodating the Entrance/Exit B, in order to ensure these utilities would not impose risks to Entrance/Exit B. Before completing the review, the MTRCL already installed additional supports for stabilisation such that the risk of loosening at the connection of the pipe was lowered, and temporarily mended the damaged part of the roof. In order to prevent similar occurrence in future, the installation of steel plates at the location concerned is being studied for further separating the structure of the station and the other underground utilities.
According to the MTRCL, the possibility of flooding in stations has been taken into account when designing all MTR stations. Arrangements have also been made to minimise the impact on the important electrical and mechanical equipment of stations in the event of flooding. As mentioned above, there are various measures in stations to prevent water seeping from the roof, wall and floor. Kerbs of 20 centimetres in height are installed on the floor at the entrances of station rooms containing electrical and mechanical facilities, to reduce the chance of water influx. Individual important electrical and mechanical facilities are installed slightly elevated to avoid being flooded. The stations are also equipped with drainage systems, which can drain the water in a rapid manner.
The MTRCL has all along put in place operational and safety manuals, covering the contingency arrangements for various incidents (including flooding). In the case of flooding, the MTRCL will fence off the affected areas as necessary and deploy additional manpower to assist passengers, while finding out the causes of flooding as soon as possible. If the affected areas cover electrical and mechanical facilities such as escalators and lifts, operation of these facilities will be suspended to ensure passengers' safety. If the incident is serious, the MTRCL will consider closing individual entrances/exits, or even the whole station. If train service is affected, the MTRCL will follow the established mechanism to disseminate information to the public through various means. When the water is drained, the MTRCL will examine the affected facilities in detail and will only reopen them after confirming that they are safe for use.
(3) The MTRCL has to consult Government departments when preparing safety manuals and contingency arrangements. These safety manuals are applicable to all railway lines, including fully automatic operation (FAO) trains. On FAO trains, passengers may get in touch with the Operations Control Centre (OCC) directly by activating the emergency call systems in trains. The OCC can obtain real-time information on train operation and situation in trains, and communicate with passengers on board directly. Generally speaking, if an incident occurs in an operating train, the train will continue its journey to the next station, because there is more space in a station to facilitate smoother evacuation, and more staff will be available to offer assistance. If the situation does not allow the train to continue its journey to the next station, emergency evacuation in the tunnel will be arranged. There are sufficient instructions, emergency lighting and ventilation in tunnels to allow passengers to evacuate orderly to a place of safety under the instruction of the MTRCL staff. During its early stage of commissioning, a MTRCL staff is currently deployed to assume duty in the FAO trains of the SIL.
The MTRCL conducts 12 to 15 drills with the Hong Kong Police Force and Fire Services Department jointly every year to simulate emergency situation and major incidents (including the situation when passengers need to evacuate in tunnels). The Government and MTRCL jointly conducted a drill in a tunnel in November last year (i.e. one month before the commissioning of SIL).
Ends/Wednesday, March 1, 2017
Issued at HKT 13:00
Issued at HKT 13:00
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