In today’s world technologies are emerging at faster rate than we expect and are implemented to achieve the organizational goals. The first question that arises in one’s mind is that, “How safe are those technologies to be used when it interacts with other factors such as humans, environmental condition etc.” In this report the case of the rail transportation of Netherlands (NS- Nederlandse Spoorwegen) is taken into consideration with the purpose of looking into safety considerations across the full life-cycle, set safety requirements, identifying the key hazards, and design to improve safety, clarification of implementation consequences and explanation about the expected outcome from the results.
Nederlandse Spoorwegen is currently divided into three company namely NSR, NS International and NS Cargo which handles the rail transportation of people within Netherlands, international rail transportation of people and transportation of cargos, respectively. Every year approximately 9 million passengers travel on NS trains and is considered as the busiest rail network in the world. Considering rail transportation as a system its modules are rolling stocks, rail network, staff, passengers, stockholders, infrastructure, OEM’s etc. Presently, NS is having two types of train running on the tracks, one is sprinter which stops at each station while travelling from source to destination and the second type is intercity which only stops at main stations during the journey.
PRELIMINARY HAZARD ANALYSIS
Preliminary hazard analysis (PHA) is a semi-quantitative analysis performed with the intention of
identifying all potential hazards and accidental events that can cause an industrial accident. This type of analysis ranks the identified accidental events according to their severity and proposes hazard controls and follow-up actions. PHA should be carried out in the early stages of a project and continue throughout the system or product’s life cycle to identify those accidental events that should be subject to a more-detailed risk analysis. The Initial study, the preliminary hazard analysis focuses on identifying immediate hazards, assessing the severity of potential accidents that could occur because of these hazards, and identifying safeguards for reducing the risks associated with the hazards. By identifying weaknesses early in the life of a system, PHA aims to save time and money that might be required for major redesign if the hazards were discovered later. Steps involved in PHA,
• Define the activity or system of interest
• Define the accident categories of interest and the accident severity categories
• Conduct review
• Use the results in decision making
• Attempts for Suicide in Railway premises
• People getting stuck in the door
• Level crossing accidents (including Pedestrians)
• Mistake from the driver
• False indication of rail signals
• Failure of the on board systems
• Collision with trams or other train
• Problems with rolling stock
• Fire in rolling stock
• Power failure
• An animal on the railway track
• Un-guarded rail crossing
• Inadequate training and drills
• Electrical blackouts can temporarily disable signals and computer systems
• Defective railway track
• Damaged overhead wires
• Unauthorized person on railway premises
• Accident involving transport of dangerous goods
• Unilaterally focused maintenance (prevent disruption of train service)
SEVERITY, OCCURRENCE AND THE DETECTION OF THE HAZARDS
The risk related to a hazardous event depends upon the frequency of occurrence and severity of its
potential consequences. The below table provides the relevant information about the frequency and
severity function in detail.
Severity of the hazards can be classified as:
Rating Severity Explanation
1 ->Negligible ->The failure results in no injuries and small damage to the system
2 -> Marginal -> The failure results in the minor injury and damage to the system
3 -> Critical -> The failure results in the major injury and minor halt in operation
4 ->Catastrophic-> The failure results in the death and complete halt in operation
The classification of likelihood of occurrence of the hazard is also represented with respect to regulation EN 50126. Occurrence frequency of the hazards can be classified as:
Rating Occurrence Explanation
1 ->Improbable ->Very unlikely, it can be assumed (once or twice 10 years)
2 ->Remote -> Unlikely but possible to occur in life of an item (once or twice 6 years)
3 ->Occasional ->Occurs some time in lifetime (once or twice in 3 years)
4 -> Probable -> Occurs several times a in a life span (once a year)
5 -> Frequent ->Occurs very frequently sever times a year (more than once)
The classification of the detection is listed below where the hazard which is completely impossible to
predict is given the highest value and the hazard which can be easily predicted is given with the least
value. The detection of the hazards can be classified as
Rating Detection Explanation
1-> Easily ->detectable Can be easily predicted
2 ->Remotely ->possible Predicted few minutes before the occurrence of the hazard
3 ->Impossible ->The hazard is completely unpredictable
Depending upon the severity, occurrence and the detection of the defect possible safety measures should be pointed well in advance to avoid further delay in recovery. Greater the value of the product’s severity, occurrence and the detection more detailed and elaborate measures must be taken to avoid the failure. The table below shows the list of hazards and their respective RPN numbers
|1||Attempts for Suicide in Railway premises||4||4||3||48|
|2||People getting stuck in the door||5||3||3||45|
|4||Level crossing accidents (including Pedestrians)||4||4||2||32|
|5||Mistake from the driver||3||3||3||27|
|6||False indication of rail signals||3||4||2||24|
|7||Failure of the onboard systems||3||4||2||24|
|8||Collision with trams or other train||5||4||1||20|
|9||Problems with rolling stock||5||2||2||20|
|10||Fire in rolling stock||2||4||2||16|
|12||An animal on the railway track||4||1||3||12|
|13||Un-guarded rail crossing||5||2||1||10|
|14||Inadequate training and drills||2||4||1||8|
|15||Electrical blackouts can temporarily disable signals and computer systems||2||4||1||8|
|16||Defective railway track||2||4||1||8|
|17||Damaged overhead wires||3||2||1||6|
|18||Unauthorized person on railway premises||1||4||1||4|
|19||Accident involving transport of dangerous goods||1||4||1||4|
|20||Unilaterally focused maintenance (prevent disruption of train service)||2||2||1||4|
DETAIL STUDY CATEGORY 1
Attempts for Suicide in Railway premises
- Securing the track with fencing or barricade (Active Safety)- By putting up barricades and fencing in locations which are easily assessable by the people or at locations where humans are rescinding.
- Adding sensors to the train to detect any human on the track (Passive Safety) – By adding sensors like infrared cameras to the front of the trains, the railway drivers can respond faster as infrared cameras can sense the presence of a human in before the human is visible and prevent the train from crashing in the human by applying brakes on time.
People getting stuck in the door
- Having an alarm every time when the door opens and closes to alert the passengers at stations (Active Safety).
- Having Security guards at the station so that the security can monitor the people to enter the train safely and to inform the driver to not move the train if anyone is stuck in between the door (Active Safety).
- Adding an Exterior door at the station to open and close the door only when the train arrives (Active Safety).
- Adding sensors to prevent the train from departing a station when people are stuck between doors (Passive Safety).
- During rush hours have a Queuing system for people and enter and depart in queue (Active Safety).
- During rush hours increase the number of security guards to control and monitor the crowd (Active Safety).
- Using sensors, we can do a real time condition monitoring to detect the failures in the system and prevent the train from derailment. This can be done by identifying the major causes for the derailment and by doing real time condition monitoring and preventive maintenance can increase the reliability of the system (Active Safety).
- Establishing a better communication system between the maintenance team (Active Safety) – Since, the rolling stock maintenance and the track maintenance are handled by two different teams, better communication among these two teams will prevent Derailment to a great extent.
- Strictly implement the maximum speed allowed at each point of the track (Active Safety) – A detailed study of the maximum speed allowed at each turn and strict implementation of the of speed controller can prevent derailment.
- Implementation of sensitive control system (Active Safety) – This system which is sensitive to seasons and can make the necessary changes in the sensitivity of the control system to the change in the weather condition with respect to the ideal weather condition.
Level crossing accidents (including Pedestrians) & Un-guarded rail crossing & An animal on the railway track
- Better communication between the level crossing and the train driver so that the train driver can control his speed or the people at the level crossing can manage the crowd and clear the track (Active Safety).
- Strictly implement the maximum speed allowed at level crossing by adding a GPS sensitive breaking system which automatically control the speed of the train in the location of the level crossing (Active Safety).
- Vegetation survey can help the train authorities to understand the density of the traffic and the population and thus necessary measures can be taken to build overhead bridges or tunnels (Active Safety).
DETAIL STUDY CATEGORY 2
- Better communication and signals must be provided to the train diver in case of collision (Active Safety).
- Implementation of a false safe system, if the minimum distance between 2 trains is less than braking distance an automatic emergency braking system must be activated to prevent collision or reduce the intensity of collision (Passive Safety).
- A regular physical test must be done on the train drivers to check if they are fit to continue driving the train (Active Safety).
- Implementation of advanced technology like Digital Twinning and Automation to improve the failsafe protocols (Active Safety).
False indication of rail signals
- Implementation of real time condition monitoring and preventive maintenance on all the sensors and signal indicators (Active Safety).
- A reliability analysis must be done on the communication system between the control unit and the train driver (Active Safety) – If the result of the analysis tells us that system is not reliable or it should be made more reliable, measures must be taken to implement better communication system between the control system and the drivers.
Failure of the onboard systems
- Implementation of real time condition monitoring and preventive maintenance on all the onboard system (Active Safety).
- A detailed failure mode study must be conducted, and necessary measures must be taken to optimize the reliability of the on-board system by either improving the capacity or the maintenance plan of the system (Active Safety).
Fire in rolling stock
- A detail failure mode analysis must be done to understand the cause for the fire in the rolling stock and with the help pareto analysis understand the critical ones and implement techniques like real time condition monitoring and predictive maintenance or make changes in the system to improve its reliability (Active Safety).
Inadequate training and drills
- Making the Maintenance training smarter – Using new techniques like virtual reality in the training of the workers (Active Safety).
Electrical blackouts can temporarily disable signals and computer systems
- As it is important to do a detailed study of the reliability of the system and make the necessary changes in either the load, capacity or the maintenance (Active Safety).
Unauthorised person on railway premises
- Improvements in the security measures taken while letting the employees inside (Active Safety).
Accident involving transport of dangerous goods
- When there is transportation of the dangerous goods, measures must be taken to understand the different hazards that might be caused due to that product and necessary measures and protocol must be created to prevent all the different ways that the product can be safely transported (Passive Safety).
DETAIL STUDY CATEGORY 3
Problems with rolling stock & Power failure
- With the help of augmented reality, simple technical issues can be solved by the driver or any untrained technician on the train without the requirement of the trained technician. Thus, reducing the down time (Passive Safety).
-Onbehalf of Group 13 (Jay Chauhan, Ashuthosh Harish, Chandra Keerthi)