The term ‘harmonic rocking’ has a ring to it for those not in the railroad industry, but to those in the know, it’s a nightmare scenario that could end up in a derailment. When harmonic rocking — a rocking from side to side — occurs to a car or a train, something is very wrong. But by the time it hits noticeable levels, it’s often too late to do anything meaningful about it. Catching it before it ever reaches that point is something that simulation training can facilitate.
Let’s see how that looks!
Heading Off Derailments
Harmonic rocking is one of the major causes of derailments. And it’s also one of the many railway dangers that simulation-augmented training can help significantly reduce, if not prevent entirely — potentially saving lives and certainly enhancing a railroad’s safety profile.
When harmonic rocking begins, it’s hard to stop, particularly as a car or train is moving at a pretty decent speed when this trouble makes itself known. When a train is moving at speeds of approximately 14-22 mph, harmonic rocking that was not discernible before can now be dangerously obvious to the naked eye. And it can culminate in a car flipping out of the train, which is no small matter. This is why it’s something to identify before the rocking becomes obvious – and dangerous.
So, how does one head it off? There are two main causes of harmonic rocking: a problem with the track or a problem with the car. We’ll explore each in turn.
Track Problems Causing Harmonic Rocking
Track conditions can feel like a railroad’s wild card, and if the entire train is rocking, the track is the likely culprit. Trains require a level, smooth ride to travel along without issue – and conductors must know ahead of time if there’s a patch of track that’s questionable and requires a slow order or slower speeds. All it takes is a quarter-inch discrepancy to send an heavily loaded or unbalanced train or car rocking.
Then there can also be broken bolts or spikes missing from tie plates. And although some wear and tear is usually easy to determine, worn track can be challenging to spot, which is where Sperry Geometry Cars come in.
Problems with the car or “freight car truck” require a human eye to capture, however. This isn’t an impossible task, of course – but there is much to be aware and keep track of. It requires an eye for detail with thorough awareness and knowledge. And a practiced eye is always best.
Train Car Problems Causing Harmonic Rocking
Beyond potentially being improperly loaded with cargo, the problem causing harmonic rocking may originate in the truck itself. There could be a problem with side frame being worn, and there’s also the bolster, axels, and side bearing rollers and blocks to consider.
For example, the roller type side bearing wedge (single or double, depending on truck tonnage) can be no more than ¾ inch apart on one end of the truck. The same goes for the left, right and diagonal measures. If the distance is greater, then it needs to be reduced to ensure there is constant contact. When properly positioned in place, movement is greatly reduced. This is an important control developed to help stabilize the truck.
The constant contact side bearing is important to watch closely for wear as well. It was developed in the middle 80’s and were designed to help stop harmonic rocking. When the body side bearing wedge is worn, inspecting the body side bearing from the end of the car (which is commonly done) can be misleading. But looking over the whole body side bearing, the worn area is quickly spotted by a trained eye – even down to a 1/8 inch discrepancy.
Another possible cause is weak, damaged, or broken springs in the spring nest underneath the bolsters. If this is the case, then a truck won’t have the correct weight available to alleviate side pressures.
Both scenarios (bearings and springs issues) should be found during the pre-departure inspection, but lots of times these things will be missed as they aren’t immediately apparent – and with a long checklist to complete, these are pretty easy to gloss over or forget. Compounding the matter, there are more than 500 different types of cars to consider and freight cars can be up to 50 years old and still running. That’s a good bit of variety and wear and tear to consider as well!
Discovering and defining each ahead of time (track and truck problems) is entirely possible with simulation training, as Heartwoods’ recent work with BNSF, Union Pacific, CSX, Norfolk Southern, Kansas City Southern, and others bears out. On-time identification is enhanced significantly, becoming second nature when workers have access to practice scenarios anytime and anywhere as a refresher.
Simulation Training for On-time Identification
Each track inspector is assigned a certain number of miles of track to inspect, with inspections happening at regular intervals, depending on the type of track. If it’s a main line track for example, it’s once every day. And every conductor has a detailed pre-departure checklist to inspect their freight train cars at least once every 1,000 miles or every 1,500 miles on extended haul trains.
With simulation-augmented training, railroad workers can clearly visualize and work through the emergency situations that result when damage is missed. And they can practice consistently identifying them to head off emergencies until these safety checks become second nature, exploring the inner workings of the track and cars to see what happens when bolster damage is overlooked, for example – as well as the bearing wedge and spring nest issues.
When a simulated pre-departure checklist is in place, many of the trouble spots leading to harmonic rocking would be identified – and that identification would continue to improve over time.
Using the sim we’ve developed for our railroad partners, employees are able to:
- Identify & measure defective rail car components
- Inspect wheels/trucks for defects
- Determine if equipment is securely coupled and if hand brakes are applied or released
- Identify safety hazards on rail cars
- Complete a Pre-Departure Inspection (CFR 215)
Watch the simulation in action here:
Heartwood’s Pre-Departure Inspection (CFR215,238) virtual interactive sim demo
The simulation allows the railroad to consistently train workers, evaluate dangerous knowledge gaps, and provide additional training to head off these emergencies at the pass. This ability to practice dangerous scenarios that would not be experienced otherwise and to see inside the train and have an in-depth understanding that’s usually reserved for mechanics provides trainees a unique, hands-on experience that cannot be achieved through other means. And simulation training is easily scalable and universally accessible, further allowing the important ‘practice makes perfect’ capability!
Heartwood is always working on new railroad simulations, including track inspection offerings – and they’re all in varying stages of development. Our goal is to offer railroads the very latest technology to keep their workers and cargo safe, and we’d love to show you how that looks. Feel free to email or call to learn more!
These are situations that regular classroom training cannot prepare workers for, and railroads including BNSF, Union Pacific, Amtrak, CSX, CN, Norfolk Southern, KCS, and others have recognized simulation training as essential to encouraging enhanced, long-term safety.
If you’d like to learn more, reach out to Heartwood directly.