Eastern Railroad Discussion > A Question On Remote DD Activation

On the NS in years past I have heard “Defect Detectors” broadcast various conditions primarily related to a.) dragging equipment b.) hot wheel (brakes) or c.) hot box (bearing failure). During the past year or so on occasions a train will clear a detector that indicates “No Defects” only to have the dispatcher contact the crew to advise that Wayside had notified them of the fact that their train when passing the last detector had a hot wheel or hot box at axle #72 for example. And on occasion have heard crews have to re-tone up a detector because its initial broadcasts got walked on.

Today I heard for the first time a detector indicate either b or c above on axle #1 and axle #30. ( 5 cars back from the head end) The crew toned up the dispatcher and advised her of the defect notification. I could only hear the dispatcher end of the communications. She advised them after checking contact Wayside and get back with her when they were on the move again. Shortly there after the crew toned up Wayside. They asked a few questions and twice asked was their train completely past the detector before they inspected their train. Again I could only hear one side of the conversation. All was good and the train was on the move again.

Sitting track side waiting on another train allowed me time to think.

Question: Can Wayside remotely activate a detector to indicate a false condition to validate that the crew properly handles the issue by the rules? Somewhat like a train master doing a “Banner Check”? Given axle #1 and #30 it won't have caused that long of a delay for the crew to check. Just a thought. Looking for a response from the experienced members on this board.

In advance, Thanks

Phil Maton
Villa Rica, GA

No, they cannot do a false report. Wayside looks for trends. If they see a bearing rise in temp continuously over two or three detectors they may have the train stop to inspect that bearing even if it didn't trip a detector. Bearings have been known to burn off between detectors, so this is an attempt to take care of a small problem before it becomes a major one.

Or using the air and one doesn't release all the way and heats up.

Yes, management can have defect detectors give out false defects, incorrect speed or axle counts to test train crews. They do have to verify that no real defects were found by the detector on the train while doing this testing.
On my class one and others we run on out west the detector desk will notify the dispatcher of any hot bearings and then the DS will notify the train to either do a running set and release, a deep set or to stop and inspect. Not all of our detectors inspect for hot boxes.

Posted from iPhone



Edited 1 time(s). Last edit at 09/14/17 16:02 by jointauthority.

It is important for a train to pull completely past a detector before stopping to conduct an inspection. Most defect detectors require a train to be moving at least 8-10 MPH in order to get a good "read".

Go too slow and a failing journal may not be turning fast enough to generate the heat needed to trip the detector. You can also go too slow and a non-defective heat source (like the ovens in the lower level of a Amtrak Superliner diner) could linger over the sensor long enough to trip it. Actually had that happen once on CSX.

Then there are the newer hotbox detectors that don't measure heat at all, they are tuned to listen for a very high-pitched squeal (well above the human threshold) that roller bearings make prior to failing. Again, go too slow and the bearing may not generate the squeal at the proper frequency to be detected.

Those sound-based detectors are but one reason why plain bearings (also incorrectly known as "flat" or "friction" bearings) have been (with minor exceptions) banned from interchange service.

When a train stops or goes too slowly over a detector, the typical message broadcast is "integrity failure", meaning the inspection was incomplete and the entire train needs to be walked.

NZ

In the case of sticking brakes where I worked you'd almost certainly get a hot wheel report instead of hotbox. Just to reiterate, where I worked (eastern carrier) there were no tests done by mgmt involving false readouts by detectors. I do not believe our signal dept would have agreed to that without a signal dept officer there too.



SD45X Wrote:
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> Or using the air and one doesn't release all the
> way and heats up.

NebraskaZephyr Wrote:
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> When a train stops or goes too slowly over a
> detector, the typical message broadcast is
> "integrity failure", meaning the inspection was
> incomplete and the entire train needs to be
> walked.
>
> NZ

On the NS here in the southeast when crew gets a "no defects..train to slow" broadcast from the detector they notify the dispatcher and are required to run at restricted speed (30 mph) until they clear the next detector.

Thanks to the experienced members that contributed to this thread!!

Phil Maton
Villa Rica, GA

I don't think restricted speed is 30 on NS, that sounds like medium speed.

Posted from iPhone

jointauthority Wrote:
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> I don't think restricted speed is 30 on NS, that
> sounds like medium speed.
>
> Posted from iPhone

You know,maybe it is 1/2 authorized speed until the next detector after thinking about it.
Thanks for the comment!!

Phil Maton
Villa Rica, GA