Platform head signage

MOONY

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15 Jan 2009
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Apologies if this can be found elsewhere, but I am interested to know what two signs seen at the head end of a platform on the Met depict:
1. "H OFF:
2. "D OFF"
Also, is there any accessible info on similar [non signalling] signage?
Any help will be much appreciated.
Moony
 
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RailUK Forums

Lewlew

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15 Oct 2019
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It's information for the drivers.

1 - Heaters off
2 - Deicer off

Those two will normally be at the end of the tunnel section going into the open section.

District Dave's website has some information, although is a little outdated.
http://districtdave.co.uk/

You also have the following
T with a cross through it - tunnel telephone wires faulty
R with a cross through it - Radio system faulty
S (or S1 or S2) - Station staff on platform doing SATS duties (despatch staff) the number is how many staff are present
 

MOONY

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15 Jan 2009
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1 - Heaters off
2 - Deicer off

Those two will normally be at the end of the tunnel section going into the open section.
Hang on a mo... why would these signs be located on the exit from a tunnel? I don't understand the relationship between tunnel and surface conditions. I think I saw them at Harrow on the Hill northbound anyway.
 

rebmcr

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Hang on a mo... why would these signs be located on the exit from a tunnel? I don't understand the relationship between tunnel and surface conditions. I think I saw them at Harrow on the Hill northbound anyway.
They're not instructions for on-train equipment, they're information about lineside equipment.
 

Lewlew

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15 Oct 2019
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London
They're not instructions for on-train equipment, they're information about lineside equipment.
Nope, they're for the on train equipment.

They aren't really used in the summer. But during the winter, you don't want the heating/deicer on in the tunnel section.

The boards will be changed to H on and D on. The last station before coming out of the tunnel is where the heaters and deicer will be switched on. Deicer is switched on before leaving the last station so that the track between there and the next station gets sprayed. Deicing equipment isn't fitted to every trains however.

The signs will be at other stations to remind drivers and for any trains reversing/entering service from Neasden for example.
 

bramling

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Nope, they're for the on train equipment.

They aren't really used in the summer. But during the winter, you don't want the heating/deicer on in the tunnel section.

The boards will be changed to H on and D on. The last station before coming out of the tunnel is where the heaters and deicer will be switched on. Deicer is switched on before leaving the last station so that the track between there and the next station gets sprayed. Deicing equipment isn't fitted to every trains however.

The signs will be at other stations to remind drivers and for any trains reversing/entering service from Neasden for example.
In reality the H boards are fairly obsolete nowadays. Originally they were placed for guards to switch the heating on and off, with heating generally not being used in tunnels. However most of today’s trains have a fully thermostatically controlled heat and vent system which drivers leave well alone, and indeed the only control is an on/off switch which isn’t routinely touched - normally only if the system is sucking in dust, or for a few drivers who turn it off at times to create a more peaceful ambience. Not sure if any stocks still have conventional heating on/off switches; 72 stock perhaps?

Likewise some lines have de-icing gear automatically controlled, although these boards are still deployed.
 

Lewlew

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15 Oct 2019
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Location
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In reality the H boards are fairly obsolete nowadays. Originally they were placed for guards to switch the heating on and off, with heating generally not being used in tunnels. However most of today’s trains have a fully thermostatically controlled heat and vent system which drivers leave well alone, and indeed the only control is an on/off switch which isn’t routinely touched - normally only if the system is sucking in dust, or for a few drivers who turn it off at times to create a more peaceful ambience. Not sure if any stocks still have conventional heating on/off switches; 72 stock perhaps?

Likewise some lines have de-icing gear automatically controlled, although these boards are still deployed.
72 stock has a button to turn off the heat and vent but as you said it's only used by some drivers to stop the noise or to stop sucking in dust.
 

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