How does a hot box detector work?

Question

How does a Hot Box detector work. Please keep it clean guys....lol

Answer 1

I'll speak to the earliest models, where they would not measure the temperature of each journal, but would indicate when one was not near the same temperature of the others.  Flawed, in that each journal on the train could be in flames but as long as near the same temperature, you'd not get an indication of an overheated journal.

And although admonished otherwise, I can't resist. The former SP Western Division hogger above will remember "Evelyn," one of that division's first female engineers to hire out in Oakland, Ca..  In fireman class when the subject of a hot box came up, she indicated she was possessed of one, to the delight of all.

Ditto for TO operator "Modoc Mary" of Oregon Division fame, but that's a RailTail...

Answer 2

Wow this stuff is good, I am an old locomotive mechanic and these guys are on it. Trains are a wonderful and addictive piece of machine to work on and the innovations have been great ! Bad bearings= flatspots..., bummer!

Answer 3

most of the answers are correct.  the HBD's do read brg temps (ifr) and compare side to side as well as to all others in a given cut of cars within certain set parameters, they will send out alerts remotely. these alerts are accessed via intranet (up) and a history of a car or complete train can be accessed for diagnostic reasons,

alerts are only one thing that car forces rely on for a heads up on defective or problematic equipment,  an escalating reading can be indicative of a failed or about to fail component or indicatative of a symptom  that leads to the root cause of the symptom or detector reading.

impact readings are used very frequently and are the largest contributer to wheelset change outs where i work.

being utilized now are hot box detectors-hot wheel detectors(pretty much the same)-cold wheel detectors-wheel impact detectors-dragging equipment & hi-wide, AEI readers.

in testing are: wheel profile scanners that take a digital snapshot of the flange/tread area of every wheel and brake shoe detectors.  a new detector array has been put into use that takes digital hi-speed-real time photos    of external safety appliances.

pretty soon a car foreman or supervisor will get a read out of  a particular train or car,  give that list to a carman and he/she goes out and fixes those defects.

i see job losses and contracting out of work

Answer 4

LMAO! Sighhh Ok fine.I had a great answer that just jumped to mind.A hot box detector scans the axles as you pass over it looking for high bearing temps and counting the number of axles.If all is good it transmits a no defect message and an axle count.If it finds one it transmits a defect message telling you what axle number and what side of the train it is on.They are usually incorporated with dragging equipment detectors.Some have impact detection looking for bad wheels.Most are radio talkers now but there are still a few remote readout detectors.In the old days it was bad to use brakes going over a detector because it would set them off.They have improved to where they ignore high heat on both sides from brakes unless they are really hot.I learned something new about them recently.The dispatcher called us and told us the computer had kicked out a car that showed an axle bearing getting hotter with each detector we passed.So we had to stop and check it and sure enough it was too hot and we had to set the car out.Good thing it found it because it was a 143 ton grain car.It doesn't take but a few miles to burn a bearing off.But i never knew a detector could do that!You learn something new every day.

Answer 5

I've never seen inside one, but I would imagine that it's an infra-red detector that triggers an alarm at the controlling signalbox (UK).

Here in the UK, hot box detectors are fixed in pairs, one on each side of the road, and must include some kind of axle counter. The reason I say this is because if your train triggers the alarm, the signaller will stop you and ask you to examine the train, telling you which side the hot box is on and how far down the train (e.g. 12th axle on the 'Up' side).

They do get confused by steam hauled specials, though.

Answer 6

Haha, clean huh, darn, in this forum that is quite a request.

Andy pretty much has it right, they work on infrared and are much more snesitive than previous versions.

Sticking brakes and hot wheels used to set them off, now they are focused much more tightly on the bearings themselves

Blowing and swirling snow can confuse them so we have instructions to slow down to 25 mph during those conditions.

When a FED (failed equipment detector) as they are correctly called detects a defect it emits a warning beep, and you get ready to stop, as soon as the entire train passes it gives you the defect(s) found and your drop off a crew member and either pull the train forward or he walks back depending on conditions.

The employee will make a determination on whether it can be corrected or if the car has to be set out.