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Southern - AirCon turned off?

atomlad

Member
Joined
26 Oct 2025
Messages
14
Location
Mole Valley
Morning all

Travelling to/from Victoria every day week and in the afternoons the carriages were quite warm. The outside temps werent that high, however the aircon appeared to be turned off and it quite stuffy with a full carriage and passengers needing to fan themselves etc. Even on Friday evening with a not so full carriage leaving London it definately was warmer than usual.

During the heatwave in June the Southern trains were very nice and cool.

Is there a policy about turning the air con off? Curious that its not automatic based on a set temp!
 
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rmHawk765

Member
Joined
8 Apr 2025
Messages
776
Location
ECML South
Occasionally 387s on Great Northern (Southern also has these, and they're very similar to 377s) just do not have the aircon switched on. Technically a train shouldn't be let out of the depot with non-functional aircon but I think it's debatable to what extent this is actually followed.

Mind you, I have taken trains in the south of France several times where it seemingly is deemed acceptable to forget about aircon despite the relatively high temperatures there throughout the year...
 

DaveTM

Member
Joined
25 Mar 2014
Messages
92
377s and 387s have two Auxilliary Converter Modules, one at each end of the train, which convert line voltage down to voltages suitable for train equipment. In each carriage there are two air conditioning units, one powered by each ACM. So if an ACM fails, each carriage will have a warm end and a cool end.

As for turning the air con off during a journey, we drivers can do that, but it would only normally be done in the event of a fire on the train to avoid moving smoke around. When we key off at the end of a journey, there is a delay of a few minutes before the saloon lights and air con turn off to save electricity, and when we key on to start a journey, they come back on without our having to do anything. So a train may be hot and stuffy for a few minutes at the start of a journey if it had a significant layover between trips.
 

williamn

Established Member
Joined
22 May 2008
Messages
1,693
I've noted the heating being on on most journeys in the last few weeks. Some trains have been sweltering. I asked staff if it was possible to turn the heating down and they said they didn't have the means to do it.
 

jack31439

Member
Joined
29 Apr 2016
Messages
81
Location
South London
The HVACs cannot be turned off and on. As @DaveTM states, they can be put into 'smoke mode' but this very rarely happens in saloons. It's more likely a defect, or as Dave states if there is no active cab for a while the HVACs enter stabling mode.
 
Joined
3 Nov 2023
Messages
87
Location
ARUNDEL
LIFE was so much EASIER when you could open the windows
But how we have heavy aircon units that use vast amounts of extra power
How "green" is that?
 

pokemonsuper9

Established Member
Joined
20 Dec 2022
Messages
4,638
Location
Greater Manchester
LIFE was so much EASIER when you could open the windows
It is also much hotter inside on those trains compared to ones with Aircon working
On 323s during the last heatwave I was mostly thinking about how it'll be nice once they are replaced by 350/2s which have Aircon while suffering in the heat not helped by windows with how hot the air was, windows barely help.
 

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