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Some trains in the Madrid metro network have small metal boxes with this sign on them:

sad face with bowtie

There are no other signs on the box and some signs only have the "bow tie".

I'm guessing it's two Zener diodes head-to-head and some sort of switch, with a rather amusing arrangement.

Can someone explain what are the components represented and their purpose?

EDIT

Thanks to everyone for their comments.

More context: I've seen this on a CAF series 8400 train. The box is approximately 40cm by 30cm, and it's located on the inside of the train, just above the floor, embedded next to a door. Unfortunately the full photo doesn't show much more.

The bow tie: It looks like @Dejvid_no1's comment is spot on. The bow tie seems to closely match a screwed globe valve (source: http://www.atperesources.com/PDF/Plumbing/plu_symbols.pdf). However, this doesn't explain the line going downward.

The sad face: After some googling, I think it could be a selector switch:

Selector switch

(image source: http://www.allaboutcircuits.com/vol_4/chpt_4/1.html#Selector%20switch)

Does this make any sense?

Community
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MBlanc
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  • That looks like an enable or gate of some sort hanging off the bottom there. – Ignacio Vazquez-Abrams Sep 07 '14 at 01:02
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    How do you know this has anything to do with electronics? – Ricardo Sep 07 '14 at 01:22
  • That just made my day. – Daniel B. Sep 07 '14 at 04:21
  • @Ricardo I had the same thought. This could be related to pneumatics or hydraulics. – Nick Alexeev Sep 07 '14 at 04:35
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    The lower part with triangles appears to be a hydraulic valve, probably with an actuator. The eyes and sad mouth is a mystery... – Dejvid_no1 Sep 07 '14 at 06:27
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    Another photo showing more context? Is this on every train, or along the tracks? On which part of the train? – MarkU Sep 07 '14 at 08:48
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    It's the NSA Conversation Interception Device - the component that listens in to all the conversations of everyone on the train. – Majenko Sep 07 '14 at 11:03
  • @NickAlexeev At the time of writing, I didn't realise it could be related to another discipline. Should this question be deleted? – MBlanc Sep 07 '14 at 22:30
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    @MBlanc I don't see a need for deleting it. There are no down- or close-votes at the moment of writing (and you probably know how trigger-happy EE.SE folks are). Having said that, if you can think of a better stack for this question, and you'd like to migrate it, then let me know. – Nick Alexeev Sep 07 '14 at 23:17

2 Answers2

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2nd symbol looks awfully like a hydraulic/pneumatic/water/other pipe control valve symbol, a few likely candidates or similar symbols can be seen here:

http://www.airlinehyd.com/webpages/information/Knowledge_Center/Symbols.aspx

http://www.plumbinghelp.ca/articles_plumbing_symbols_valves.php

1st one could be any sort of circuit breaker, switch, etc.

The problem here is that we don't know what the box is controlling, and institutions like rail, sea, air, power companies, telcos etc. will often have their own defined standards for things like this to suit for the specific nature of their systems, avoid ambiguity, and as a side-effect ensure that outsiders can't be 100% sure what the symbol means.

For all we know that could change the points on the track & redirect the trains (mechanical), or it could empty the contents of the train toilet (plumbing), or any other system on a train.

John U
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Could be the de-coupler for disconnecting the car from the one next to it.

Ken Williams
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