Mk3 mystery fitting.

[Ashley Hill]

Hello,can I trawl the expert knowledge on this item found on Mk3 coaches. Basically what is it? It’s marked in the wiki photo by my rough arrow. I thought it may be something to do with the jacking point below but it’s only at one end of the coach.

 

[zwk500]

Also visible in this, slightly higher resolution view: https://upload.wikimedia.org/wikipedia/commons/d/d9/Ponsadane_-_GWR_Mark_3_TS_42087.JPG

 

[NoOnesFool]

I wonder if it is to do with the air pressure in the carriage. For example, it might be to aleviate air pressure as it passes through the tunnel.

Trivia
Aeroplanes have a small hole in the cabin windows to regulate air pressure.

 

[Ashley Hill]

Here’s another wiki photo showing it clearer. Circled in red.

 

[nlogax]

I've seen these on LNER, GWR and Scotrail stock. Something to do with gauge monitoring?

 

[y3j]

RFID tag.

 

[Ashley Hill]

RFID tag.

I googled this. So is this to positively ID the vehicle and track it?

 

[43096]

I googled this. So is this to positively ID the vehicle and track it?

The primary use is for vehicle identification on lineside equipment such as WILD/HABD/wheelchex/gotcha.

* WILD = Wheel Impact Load Detector, HABD = Hot Axle Box Detector

 

[Undiscovered]

RFID tag.

It's quite a way above the railhead.
While it's possible, you'd need a big field dispersal to excite, interrogate and receive the chip information.

 

[Ashley Hill]

Thanks for all your answers,I am now better informed.

 

[edwin_m]

RFID tag was my first thought too, though I don't know for sure.

The Panchex equipment installed in the 1990s used an earlier and larger but otherwise similar RFID tag, fitted to electric stock at about passenger shoulder height below the pantograph. Even before that there was a larger still tag about the size and shape of a fruit cake bolted underneath HAA wagons as part of a scheme to track coal loads.

 

[Ashley Hill]

Today I am even more informed. It seems some routes are fitted with devices that monitor the wheel bearing harmonic frequency of passing vehicles. Each wheel bearing it seems has a unique harmonic frequency. As a vehicle passes such a detector it identifies the vehicle from the RFID and reads the harmonic frequency of the wheel bearings. Changes in harmonic frequency since the last reading indicates there has been wear in the bearing.

 

[Efini92]

RFID tag was my first thought too, though I don't know for sure.

The Panchex equipment installed in the 1990s used an earlier and larger but otherwise similar RFID tag, fitted to electric stock at about passenger shoulder height below the pantograph. Even before that there was a larger still tag about the size and shape of a fruit cake bolted underneath HAA wagons as part of a scheme to track coal loads.

Why does the panchex have a pantograph?

 

[nlogax]

Today I am even more informed. It seems some routes are fitted with devices that monitor the wheel bearing harmonic frequency of passing vehicles. Each wheel bearing it seems has a unique harmonic frequency. As a vehicle passes such a detector it identifies the vehicle from the RFID and reads the harmonic frequency of the wheel bearings. Changes in harmonic frequency since the last reading indicates there has been wear in the bearing.

That's an excellent proactive use of technology on the railway I'd not previously heard about at all. Thanks for sharing.

 

[fgwrich]

That's an excellent proactive use of technology on the railway I'd not previously heard about at all. Thanks for sharing.

GOTCHA is certainly an impressive bit of kit. Siemens has a similar system (RailBAM) which knows when a Desiro is about to pass and listens to the axles and bearings, then feeds back the data to Siemens directly.

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[Ashley Hill]

GOTCHA is always an acronym that has amused me. I always thought it was an award that Noel Edmonds used to hand out. Sometimes I think the railway creates an amusing acronym then finds the words to fit it!

 

[edwin_m]

Why does the panchex have a pantograph?

Panchex was (I think it's now superseded by something more modern) a piece of equipment fitted to the overhead line to monitor the pantographs of passing trains, and didn't itself have a pantograph. The RFID tag was fitted to teh trains using the route, and allowed it to include the loco/unit number when it detected a fault.