I live in a small town (population around 6,000) in central Virginia. The east coast railroad runs through it. Each day we see about 65 freight trains (CSX) and around 15 passenger trains (Amtrak). In recent months we have experienced a startling number of train/vehicle collisions. They are summarized here.
The most recent event (just last week) is shown in this YouTube video. The sequence of events was as follows:
- A train was approaching the local station. It was daylight, weather conditions were normal and road traffic was light.
- The barriers went down to prevent vehicles from crossing the tracks.
- Two vehicles did approach the barriers. The drivers chose to take another route.
- Then a car drove straight into the crossing (through the barrier) just as the train was approaching.
- The train hit the car. We are told that the car driver sustained minor injuries. She was lucky. If she had been a few seconds earlier the train would have run right into her car rather than side swiping it.
For this, and for all the other events, the cause of the accident has been that a car was driven on to the tracks. In some cases the car was able to bounce off the tracks, in other cases a passing train was on the other track. But, in many cases, the car was hit by a train. Each event occurred in normal weather conditions and the crossings are well marked and well lit at night. Fortunately, to date, we have not experienced a fatality or any serious injuries.
What to do?
People in our community correctly note that these events are all caused by human error. We don’t know the causes of the errors. These may include simple carelessness, inebriation, distraction due to the use of a mobile phone while driving, or even suicidal tendencies. We don’t know. Nevertheless, a common response is to say that drivers should be “more careful”. (Some people also recognize that hardware improvements to the gates and the painted lines on the road can be made — indeed fresh lines were added to the busiest crossing just a few days before the latest event.)
But all of these response are “off the cuff” and focus on changing driver behavior. However a formal risk analysis may offer better insights and may help identify root causes.
Formal Risk Analysis
Risk, as we all know, consists of four elements:
- A hazard — a situation that has the potential to cause harm.
- The consequences of that hazard. In this case the consequences are injury or death of the car driver, complete loss of the vehicle and damage to the train’s locomotive.
- The frequency with which the event occurs. In our case these events are occurring close to once every month or two — a number that is obviously much too high.
- The safeguards that help either prevent the event from occurring, or reduce the consequences and/or frequency if it does occur.
Those of us who are trained in process safety might want to consider a formal risk analysis of these events to see if we can come up with root causes.
First we ask, “Can we remove the hazard?”. (Trevor Kletz is famous for saying, “If a tank’s not there it can’t leak”. In this case, the phrase could be, “If a train’s not there it can’t hit a car”.)
The hazard here is that trains and cars are occupying the same space at the same time. Collisions are inevitable — risk can never be zero. However, if we separate the road from the tracks, say by building a bridge or a tunnel, then the risk associated with a train/car collision does drop to zero. (In this context the Virginia legislature is to be complimented — State law states that new crossings cannot be at grade.)
The second item to look at is the consequence term. On process facilities reducing the consequences of an event can be done through actions such as installing a system that diverts released gas to a flare or blowdown system. Unfortunately it is difficult to think of a means of reducing the consequences to do with a train/car collision.
The frequency with which these collisions occur can be reduced by redirecting cars to other roads which are less congested. This is something that is being looked at as part of a program to improve the town’s overall traffic congestion problem. The frequency can also be reduced by generic programs to do with driver training, and checking those who might be driving under the influence.
Finally, more safeguards can be provided. These include more visible barriers, more flashing lights, louder horns at the intersection and installing floodlights for night-time operations.
The best way of reducing risk is to analyze a situation using the four elements listed above in the order that they are listed. And always, the best response to a risky situation is to remove the hazard. That is the only way in which risk can be reduced to zero.
Public awareness to do with these events has increased enormously due to the fact that a video camera has been installed at the critical junction by a railway enthusiast group. Similarly we are seeing more and more actual events at process facilities because security cameras are becoming so pervasive. (For a dramatic illustration of what a process plant explosion can look like take a look at the Reynosa event, starting at 0:30.)
A picture is worth a thousand words and a video is worth a thousand pictures.