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What is the HABD?

You are here: Home > Forum > Simulations > Released > Carlisle > What is the HABD?

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What is the HABD? 04/08/2020 at 21:33 #130377
manadude2
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Not mentioned in the manual, just wondering what the HABD is on the Up Goods just past Floriston LC, and why a train would need to be clear of it in order to be signalled into the yard (Route is not available from CE487 until this indicator lights)?


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What is the HABD? 04/08/2020 at 21:34 #130378
Steamer
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Per the manual:

Quote:
Before a train can be sent into the yard the block must be indicating either white or green. In addition to this the route from CE487 cannot be set until the train has passed over the Hot Axle Box detector at Floriston Level Crossing.
Not sure why passing the HABD is required to set the route into the yard.

"Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q)
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What is the HABD? 04/08/2020 at 21:38 #130379
manadude2
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Steamer in post 130378 said:
Per the manual:

Quote:
Before a train can be sent into the yard the block must be indicating either white or green. In addition to this the route from CE487 cannot be set until the train has passed over the Hot Axle Box detector at Floriston Level Crossing.
Not sure why passing the HABD is required to set the route into the yard.
Ah, I was searching for "HABD". Could be a fire risk for flammable goods in the yard?

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What is the HABD? 04/08/2020 at 21:41 #130381
Humorist
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manadude2 in post 130379 said:
Steamer in post 130378 said:
Per the manual:

Quote:
Before a train can be sent into the yard the block must be indicating either white or green. In addition to this the route from CE487 cannot be set until the train has passed over the Hot Axle Box detector at Floriston Level Crossing.
Not sure why passing the HABD is required to set the route into the yard.
Ah, I was searching for "HABD". Could be a fire risk for flammable goods in the yard?


Wasn't there an era when the explosives wagons from Ardeer were frequently running hot, with obviously hazardous potential consequences? That would be a reason to install the HABD.

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What is the HABD? 04/08/2020 at 21:42 #130382
manadude2
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I also suppose that's what these indicators are too, hot axle box detectors. That solves another mystery!


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What is the HABD? 05/08/2020 at 05:01 #130391
Chromatix
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Axle boxes are a rather critical part of a moving train. Occasionally, a fault will develop in one - maybe the oil or grease leaks out, or a roller deforms and jams - which manifests itself as a significant increase in friction and thus generated heat, allowing the fault to be detected by automatic means (or, in the old days, by feeling the axlebox for heat at the same time as tapping the wheels for cracks). Sometimes a "hot box" can also be detected visually by a plume of smoke. A related problem would be a dragging brake block or shoe.

These faults tend to progress fairly rapidly due to a greatly increased wear rate and, in extreme cases, can result in the axle seizing completely or outright falling off the wagon (in which case you are having a big problem and will not go to space today), so HABDs are installed at strategic intervals on the main lines. If one triggers, the signalman is supposed to stop the train somewhere and have it examined for defects, and usually there is a loop or a goods line and cripple siding conveniently located for this purpose, a few signals in advance from the HABD itself. This is what the "stop and examine" bell code is for in AB regulations.

In the case of Carlisle, the HABDs at Floriston allow a train routed into Kingmoor New Yard to be stopped there, and a train on the main line to be stopped in the Kingmoor Up Loop or Up Through Siding. There is another HABD on the Up Main on approach to Shap Summit. In the Down direction there is one at Grayrigg (where a train can be stopped at Tebay) and on both the Down Main and Down M&C on approach to Carlisle. Trains approaching on the Newcastle and Settle lines rely on visual examination by the AB signalmen on those routes.

Last edited: 05/08/2020 at 05:04 by Chromatix
Reason: None given

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What is the HABD? 05/08/2020 at 05:07 #130393
GeoffM
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For the fun factor, run a steam engine over the HABD. Then decide if it's a fault that needs examining, or it's the firebox setting it off falsely.

(I'm sure somebody can fill me in on the rules in such cases here)

SimSig Boss
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What is the HABD? 05/08/2020 at 05:29 #130394
Hawk777
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Do these hot axle box detectors ever trip in SimSig, or are the roundels purely decorative (other than the one that restricts yard entry)?
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What is the HABD? 05/08/2020 at 05:58 #130395
GeoffM
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Hawk777 in post 130394 said:
Do these hot axle box detectors ever trip in SimSig, or are the roundels purely decorative (other than the one that restricts yard entry)?
Depends on the sim.

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What is the HABD? 05/08/2020 at 09:12 #130396
kbarber
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Hot boxes have the potential to cause a lot of havoc. Anyone who recalls the Summit Tunnel fire of 1984 will have an idea what I'm talking about. That was the result of a roller bearing failing, something that can happen relatively quickly and progress rapidly to catastrophic failure. A HABD will usually detect them before they reach the point that lubrication is compromised and catastrophic failure becomes possible. They're invariably located some distance in rear of a suitable loop where a train can be put inside for examination.

Back in dinosaur days, most wagons had plain journal bearings. When those ran hot, there would be a plume of smoke (as Chromatix says). Even before smoke became visible there would be a distinctive smell that would alert a signalman. But they could continue to run at suitably reduced speed to the next location where they could be put off the train and 'red carded'. After a C&W examiner ('tapper'had looked at the failed 'box, the wagon would be labelled with a red and green card (yard to yard for repairs) and could be taken to the nearest point where transhipping could be carried out, thence to the workshops for lifting. The combination of greater fault tolerance in a journal bearing and frequent signalboxes made catastrophic bearing failure something of a rarity, though hot boxes were actually very frequent.

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What is the HABD? 05/08/2020 at 10:14 #130399
Chromatix
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Yes, stuff like Summit Tunnel is what I was referring to with "you are having a very big problem and will not go to space today". (It's a quote from Randall Munroe's Thing Explainer, on the Up Goer Five page.)
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What is the HABD? 05/08/2020 at 10:24 #130401
VInce
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GeoffM in post 130393 said:
For the fun factor, run a steam engine over the HABD. Then decide if it's a fault that needs examining, or it's the firebox setting it off falsely.

(I'm sure somebody can fill me in on the rules in such cases here)
1st gen DMUs too.

The hot exhaust running from the engine between the bogies used to set them off too...

Vince

I walk around inside the questions of my day, I navigate the inner reaches of my disarray, I pass the altars where fools and thieves hold sway, I wait for night to come and lift this dread away : Jackson Browne - The Night Inside Me
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What is the HABD? 05/08/2020 at 10:28 #130402
headshot119
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Chromatix in post 130391 said:

In the case of Carlisle, the HABDs at Floriston allow a train routed into Kingmoor New Yard to be stopped there, and a train on the main line to be stopped in the Kingmoor Up Loop or Up Through Siding. There is another HABD on the Up Main on approach to Shap Summit. In the Down direction there is one at Grayrigg (where a train can be stopped at Tebay) and on both the Down Main and Down M&C on approach to Carlisle. Trains approaching on the Newcastle and Settle lines rely on visual examination by the AB signalmen on those routes.
Just for a complete record there's a HABD just the Carlisle side of Wetheral on the Down Newcastle.

"As the last track dropped, and the route became free, came the cry BROMLEY " - Opinions are my own and not those of my employer
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What is the HABD? 05/08/2020 at 19:49 #130407
Sam Tugwell
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Each Signalbox or Workstation will have instructions on what to do when each specific hot axle box detector is activated. This will vary for passenger or goods trains as well. An example being the HABD on the Up Tunnel line at Pilning, all trains are stopped at the signal protecting the junction at Patchway and are examined. The HABD will give the exact axle number to make this a faster process. They then proceed to a platform at Bristol Parkway (for passenger trains) or the Freightliner Yard at Stoke Gifford (for freight trains).

A similar example to the one mentioned by the OP is on the Up Main (in the down direction) between Swindon and Wootton Bassett Junction. There is an SBSI for the Swindon desk when running reversibly not to clear the route over Wootton Bassett Junction until the train has passed over the HABD in case it needs to stop and carry out the examination instructions at the junction.

"Temple Meads Signalman"
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What is the HABD? 05/08/2020 at 20:09 #130408
TUT
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Also seems to be a favourite topic for rules competency tests
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