SUBMISSION TOTHE RAILWAY SAFETY ACT REVIEW ADVISORY PANEL
BY:
PROF HUGH PHILLIPS PHD.
THE PROBLEM
INFRASTRUCTURE AND OPERATIONS
There may be, if not a disconnection, then perhaps a less than prefect join between rail infrastructure and train operations in assessing rail safety. However they are conjointly causes of both in the incidence of accidents and the severity of such accidents.
Examples:
- The direct cause of an accident may be defective track but it becomes severe when the cargo is hazardous.
- The track may be in good condition for regular operations but an accident may be caused by say the speed of the train or its length.
Thus both infrastructure and operations are integral in the level of rail safety in Canada.
Collateral damage
Currently the focus appears to be on the number of accidents, in contrast the public concern is the damage caused by accidents. In other words, the key factor is not the incident of accidents per se but death, injury, collateral damage, including of course pollution, caused by those accidents.
Examples:
- The accident at Montmagny QC is concerning but the Squamish accident was a disaster.
- In Decmeber 2005 there was another accident near Squamish. Howeber, in this case, it involved seven empty chip and lumber cars. This was obviously concernng but in no way as serous as when the accident involved 40,000 litres of caustic soda being dumped into the Cheakamus River.
Again this re-infomrces the integral reationship between the infrastrautre and oppertaions, in evaluating rail safty.
A DIRECTION
Identifying the key areas
Obviously to produce risk-free, or even something even approaching a risk free, rail network is impractical to the point of being impossible. In both my academic work and when advising major organisations, I frequently encounter this issue of the daunting scope of the problem.
However the accepted general rule is that if you can identify the top 10% of problem areas and address them, you have dealt with 60% of the total problem. (If you can identify 20% of the areas, than this level rises to 80 %.)
Manipulation both sides of the equation.
As the impact of accidents is the net effect of both infrastructure and operations, then either side of the equation can be manipulated to address that problem.
Case study
I live in Boucherville QC. We have just four trains a day, travelling at 30 miles and hour. Under normal conditions I would not be bothered by them.
However, the trains carry highly hazardous and explosive cargoes, within yards of residential buildings. Thus if there was an accident, then it would be of unimaginable proportions. In other words, if you combine infrastructure and operations you have what can only be described as a travelling bomb. (In this respect, I would refer you to the District of Columbia’s 2005 inquiry into transporting hazardous materials though their territory)
If you are so inclined, this can be converted into an equation.
Rail safety = P 1 (probability of an accident) * P 2 (probability of major concomitant damage)
MANAGEMENT SCIENCE APPROACH
There are many other areas that similar to Boucherville. These are relatively easy and low cost to identify.
The factors contributing to rail safety are well known – length of trains, bends, speed etc. and of course what is regularly carried on that track.
A simple review of the network will identify the high risk areas - a small fraction of the total - which then constitute the priorities.
These can be addressed by both sides of the infrastructure - operations equation.
Returning to my case study of Boucherville, there is a night train. It is well known that the impact (death, injury etc) of an accident at night is four times as high as during the day. Therefore it become a simple trade off – is the cost of rescheduling the night train until the day justified by a four fold increase in rail safety? Alternatively what is the trade-off between cost and safety of reducing speed?
Assessing the risk
At the risk of being over scientific at this stage, may I outline the usual procedure in these cases? The approach normally used is to construct a simple weighting index, a set of key causal factors. This can be done initially be the Delphic Approach, that is based on reasonable assumptions by experts.
The network is then reviewed against these criteria. This should be a routine task – low cost, office based and relatively simple.
The top 10% (initially, then the top 20%) are then identified, as priority areas.
The next step is to asses the impact on the safety level, of addressing one or more of the factors contributing to that high ranking. Which of these are feasible to address, to reduce the high rating to acceptable levels?
Example 1.
A long train crossing a trestle bridge at 60 miles per hour, on a curve and regularly carrying hazardous cargoes at night represent a major risk
Obviously it would probably be prohibitively expensive to straighten the tack but reducing speed may reduce the hazard level to acceptable levels. If this was not feasible for operational reasons, would reducing the length of trains reduce the risk to acceptable levels? And so on and so on, the process can be re-iterated until the optimum solution is found.
Example 2
If the train was a passenger train and so reducing speed or length were not feasible, then you might have to consider reconfiguring the curve. However, at least an order of magnitude has been placed on the risk profile across the network, to guide investment priorities.
SUMMARY
Public concern is not with the incidence of accidents but their impact - in terms of death, injury, pollution and other collateral damage. The ‘safety’ level is therefore, the child of the marriage of both infrastructure and operations.
Using modern Management Science approaches may help to economically, quickly and effectively identify the key priority areas to address to improve rail safety.
EPILOGUE
Being from the Montreal area, there is always in the back of our minds, the evolving findings of the Laval overpass enquiry. The priority, the time, the money and the concern appears to being focused on ascribing responsibility after an accident and not on identifying potential accidents before they can happen. Pubic concern is not, why did it happen, but rather why was it allowed to happen?
Prof Hugh Phillips PhD.