Do you have a temperature gauge in your car? Many cars no longer do, but if yours does and you were driving down the road and you noticed the temperature rising you would probably keep an eye on it and if it began to rise steadily, it would be smart to stop and check things out before the needle was pegged in the red zone.
The just released NTSB report describes the sequence of events leading up to the derailment in a very matter of fact manner, so you need to read it carefully and think about it. They describe the train passing a series of HBDs (Hot Bearing Detectors):
At MP 79.9, the suspect bearing from the 23rd car had a recorded temperature of 38°F above ambient temperature. When train 32N passed the next HBD, at MP 69.01, the bearing’s recorded temperature was 103°F above ambient. The third HBD, at MP 49.81, recorded the suspect bearing’s temperature at 253°F above ambient. NS has established the following HBD alarm thresholds (above ambient temperature) and criteria for bearings:
- Between 170°F and 200°F, warm bearing (non-critical); stop and inspect
- A difference between bearings on the same axle greater than or equal to 115°F (non-critical); stop and inspect
- Greater than 200°F (critical); set out railcar
The crew received an audible alarm at the last HBD of a critical temperature and they began stopping the train, but it was too late to avoid the derailment as the bearing failed.
Look at the mile markers where the detectors were placed, 79, 69 and 49, spaced 10 miles apart and 20 miles apart. If the temperature rose 65 degrees from 38 degrees above ambient to 103 degrees in ten miles, then it’s easy to see it will be well past critical temperature in another twenty miles, that temperature gauge will be pegged in the red and just like in your car, you would see that coming and begin stopping immediately before that happened. As the report describes, the crew received an audible alarm at mile post 49, too late to prevent the cars from derailing.
Questions not answered:
- Is there any indicator in the locomotive that warns the crew of rapidly rising, but not yet critical temperatures or is it the equivalent of an idiot light in a car, going off after the fact? If not, why not?
- Why was there a twenty mile gap between the last two detectors instead of a ten mile gap like the first two?
Railroad safety issues are important in North East
These questions may or may not be answered in the coming days, but as obvious from our article on the live train cameras, those of us in North East have a real interest in rail safety with the large number of trains passing through town every day.
Note: Remember the days when each train had a caboose? The guys riding back there had the job of keeping an eye out for hot boxes, but now, it’s all sensors, no caboose and trains so long you can’t see all the way to the end anyway.
It concludes with four recommendations:
- Review existing HBD system inspection and maintenance policies and procedures for compliance with existing industry standards and manufacturer recommendations for HBDs
- Review existing procedures to train and qualify personnel responsible for installing, inspecting, and maintaining HBDs to ensure they have the appropriate knowledge and skills.
- Review current HBD detector thresholds in light of recent derailments, and all other relevant available data (including data from any close calls or near misses), to determine the adequacy of the railroad’s current thresholds. Thresholds should be established for single measurement as well as multiple measurements of individual bearings to enable temperature trend analysis.
- Review current procedures governing actions responding to HBD alerts to ensure required actions are commensurate with the risk of the operation involved.
Note the highlighted portion in number 3, it calls for trend analysis, which is exactly what I asked about in my first question in the article above.
The advisory is worth reading in its entirety because a number of very interesting points are raised. It’s available at the link below.