Abstract:
Natural disasters have been known to humans ever since the formation of early civilizations. However,
as increased human interventions contribute to the destabilization of the natural balance of
environmental processes, even more frequent occurrence of natural calamities are occurring today.
Prediction, prevention and planning/installing, detection/warning systems are very important
components before a disaster. The evacuation procedure should start only once the tsunami arrival
information is confirmed. Since Sri Lankan coastal railway lines typically do not have branch lines
running inland, trains cannot be detoured during the evacuation procedure. Thus, the in-line
evacuation process should be well planned and guidelines made known to the operator and the users.
In this study, the South-West coastal railway line in Sri Lanka is analysed to identify the operation &
evacuation of trains under a tsunami warning. The "safe" railway stations are identified depending on
the station elevation with respect to the mean sea level, the capacity to store trains, and the number of
tracks. It is assumed that, at a minimum, the railway control centre can be equipped to detect, and
communicate with, all the trains and stations along the coastal line at any instance. The nearest "safe"
and "unsafe" railway stations for each train, and the travel time to them, are determined with respect
to the location and direction of each train atthe warning time.
Travel times to each station are analysed depending on the distance and possible speed of a train. If
there is sufficient time, trains are directed to a safe station; otherwise, to an unsafe station. If a train is
sent to an unsafe station, passengers must be evacuated immediately. Short notice of a tsunami may
also require evacuation of passengers at the nearest possible safe evacuation location, due to lack of
time to reach any railway station.
A methodology is proposed to identify the operational control of trains under different tsunami warning
times, wave heights and locations of trains relative to stations. The confusion and concern that will
prevail among passengers is considered. The poor communication and signal systems in place are
considered. Planning guidelines are proposed to improve communication, select safe stations under
various tsunami scenarios, as well as select evacuation stations. A procedure for assigning trains to safe
or evacuation stations is also advanced.
