Railway Protection

Control Criteria of Effects on Railway from Adjacent Construction Works

The Operating Railway comprises the Tsuen Wan Line, Kwun Tong Line, Island Line, Tseung Kwan O Line, Tung Chung Line, Airport Express, Disneyland Resort Line, West Rail Line, East Rail Line, Ma On Shan Line and Light Rail.

Limiting Figures

Pressure change on any underground structure / installation (P) - 20 kPa ≤ P ≤ 20 kPa
Movement ≤ 20 mm for a total movement in any railway structures / installations
≤ 1 in 1000 for distortion in any railway structures / installations
≤ 5mm for the induced level difference between rails of a track in perpendicular plane
Vibration induced to railway structures ppv ≤ 15 mm/s (prolonged)
ppv ≤ 25 mm/s (blasting)
Vibration measured on the overhead power line mast, signalling and telecommunication furniture on at-grade railway structures ppv ≤ 10mm/s
amp. ≤ 80 £gm

Clearance Requirements

Pile, foundation, borehole/drillhole, well, soil nail, horizontal drain, rock bolt/dowel or other geotechnical installation ≥ 3m from underground railway structures
Piling works adjacent to at-grade railway structures; ≥ 3m on plan from the railway fence/wall, or 7m on plan from the centreline of the nearest track when there is no railway fence or wall
Scaffolding, working platforms, advertising signs or any projections ≥ 6m on plan from track if erection at a level above the railway tracks
Operation of lifting appliance ≥ 6m on plan from tracks and above ground structures / installations for the arc in which the jib of lifting appliance swings
Storage of materials, containers, huts etc. ≥ 6m on plan from railway structure / track and vent shaft openings
Storage of dangerous goods or other inflammable materials ≥ 6m on plan from railway structure / track
Openings of building ≥ 5m to the opening of any railway vent shaft. This distance may be reduced to 2.5m if the exhaust air from the railway vent shaft is directed away from the vent shaft opening and is not likely to affect the opening by natural convection

*The control criteria are extracted from PNAP APP-24 and PNRC 14 for reference only.