Figure 8: The Bukit Lanjan rockfall along the New Klang Valley Expressway, in November 2003, resulted in a six month closure of that particular stretch 43
return period. Local weather changes are among the natural causes that triggered the flash flood 10.
ii) Landslide Asia suffers more landslides compared to other world regions due to climate. According to United Nations University 11, among natural disasters, landslides are the seventh ranked killer, after windstorms, floods, droughts, earthquakes, volcanos and extreme temperatures. An average of 940 people were killed annually by landslides in the decade 1993 to 2002, and most of these victims were from Asia. There are many factors which can trigger landslides including changes of slope geometry, changes of water level, rainfall intensity, and changes in loading. However, the major cause of landslides in Malaysia is high precipitation 12.
Figure 8 shows that after a rockfall due to landslide, vehicles can still swerve and go around the debris. Trains do not have this option, even if a small landslide occurs on the railway line. This brings greater risk to the trains and passengers. It is important for the infrastructure manager to design the slope and track embankment with the consideration of extreme rainfall due to climate change.
A study from the UK demonstrates the disruption caused by the impact of weather on railway lines. The wettest winter on record in England and Wales( 2013-2014) caused widespread and severe consequences including flooding and disruption to road transport in the
Figure 9: The main railway line to Cornwall and Devon was demolished at Dawlish by storms which hit the UK in February 2014 45
Somerset Levels. It also caused the destruction of the South Devon Railway sea wall at Dawlish( refer to Figure 9), severing rail access to and from the counties of Cornwall and Devon and the rest of the country. 13.
There are many consequences to the railway infrastructure due to hot and dry weather and the obvious example is the risk of buckling. According to Network Rail, the definition of buckling is the extent of track deformation constituting a reportable buckle is that which would render the line unfit for the passage of trains at line speed and / or necessitates emergency remedial work under the cover of either a temporary restriction of speed or closure of the line. Buckling is very treacherous as it could cause derailment to the train and end up disruption of railway operation service. Figure 10 shows a Singapore bound train derailed on January 26, 2013 due to rail buckling 5, 14-17. The wagons landed on their sides and trapped the worker and injured five passengers. The train service to the southern part of Malaysia was disrupted for several days due to the difficulties of rescuers to reach the remote area where the incident happened.
Infrastructure Adaptation to Climate Change
Malaysia has conducted several studies on climate change scenarios through the Malaysian Meteorological Department and the Ministry
51