Great Western Coffee Shop

The 1808 from Reading, is very hot, with no windows. Does the air con normally work on these units?

Yes.  Too well normally.

Ah ok cheers, reason why i ask is because i heard some sort of ventaliation system on the ceiling of the Class 180 coach C blowing air through, and i wonder if it was hot air rather than cold air, if so what system is the air con linked up to draw in this hot air?

Apart from that a bit unusual to see a Class 180 working a Semi fast service calling at Twyford, Maidenhead, Slough, Hayes, Ealing Broadway and Paddington.
On the plus side at least the driver or guard (dont know which) have some useful info to passengers about 'If you travelling to London Paddington, you need to deboard here and travel on the other fast services as this particular one, the one i was on would take 54minutes instead of 30 minutes' although people didnt look that bothered about the announcement... Strange. Maybe there wanted a stuffy hot train who knows  ;D

The system is all one big system which either heats, cools or vents air depending on what temperature the sensors in the carriage are recording.  If those sensors are faulty, or the cooling/heating elements are faulty it might lead to a hot coach, but this is quite unusual in a Class 180.


Make the most of it as it's reverting to a Turbo as of Monday until at least December.

Oh good, the return of the lovely turbo. I foresee cold conditions on the trains if the weather changes.

Thankyou, i now have a better understanding of air con system. However this heat on Class 180 was at the beginning of service so goodness knows how hot it got in the end...

The system only works while the engine is running.

So if it's at the start of the day / been laid up during the day etc, it will start out warm, until the circulation gets going.

I understand that there is a legal H&S requirement on forced air circulation in sealed coaches - so many litres of air per minute need to be forced through - or at least be designed to do so. This can be heated / cooled by use of thermostats as required.

Only when the engine is on? so you're telling me that the adelante's air con only works when that happens, that's ridiculous really. What did FGW do to improve the adelantes apart from the door fixing and engine fixing? Did it not look at a system of air con that operates also when the engine is off, or is that due to cost? If it is cost then provide windows as on the turbo's

Well had the 1808 been severely overcrowded then it would have breached that H&S requirement, or tho tbh maybe we need to give FGW a break so they can look into the air con again. Always a third chance... and do those thermostats work not when i have been on them.
Sorry for the heavy questioning but this does need action taken on all the 180's that have the air con that fails.
P.S i bet people missed the regular turbo train on the 1808 yesterday  ;D

James, I think you are old enough to think things through?

How would you power the aircon when a disel engine is switched off? Where is the power going to come from?

Well ChrisB, thats simple erm...
Lets be realistic ok, if a electric switch was provided on its know for the aircon (without needing to start the engine, my gosh look at how much fuel you could save) then it could operate that way, or is that too technical and costly for fgw...

On its know?

Oh my gosh, right lets be simple so you can understand....
If a wire was connected too all the coaches of the train and onto the air con with one switch in the cab for air con only (as on aircraft and cars) then it should work. Are you really telling me that no trains have this function?

James - I don't think you've answered ChrisB's point about where the power to operate the air conditioning would come from if the engines weren't running.   Lights are all well and good from limited batteries, but aircon would drain them very quickly indeed with little effect.

"On its know" confused me too - I think you meant "on its own" - and that was clarified by your later post. But it wasn't that it needed simplifying for the rest of us - rather than it needed clarifying.

The power to air-condition a whole train is quite a lot.  180s generally have very good air conditioning which starts working fully within a couple of minutes of the engines being switched on.  It is very rare to have passengers on board whilst the engines are switched off on a Class 180 anyway, so the whole argument is pretty academic.  HST's are no different - if the carriages aren't getting a supply from one of the power cars with its engine switched on then there is no air-con after a very short while.

If there is an air-conditioning fault, inform the train manager who might be able to get it working by resetting the system and if not it can get booked in for repairs at the end of service.  If you can, try a different carriage, or even the other end of the carriage you are in - like the Turbo's there are more than one thermostat in each carriage, so the temperature can be noticeably different in each end of the carriage.  In rare cases when the heat is exceptional then that carriage or the whole train may need to be taken out of service.

Cheers Grahame. I hope ChrisB understands were i am coming from then from the latter post i made.
Just surprises me that no alternative is provided to power the aircon other than the engines... maybe like i said before ' this needs looking more into.'

Yes thank you for that, tbh Coach C was over the heat marker, and i was going to tell someone but was in a rush, but nevermind, maybe its sorted out now you never know :)

I am far from an expert in such things, but I understand the aircon fitted to most if not all diesel trains depends in part on the air outside moving to cool things like heat exchangers.  It therefore follows that for the train to move the engine has to be running.  Whether it is different for electric stock I don't know.  There might well be issues with too much current being required for the infrastructure available.

They are not the same as air conditioning units fitted into buildings which require large amounts of current and are usually the first things to be switched off when the power fails and a generator kicks in.

The power required for aircon is so significant that on most AC EMUs I can think of the aircon automatically goes off whenever the train passes under an OHLE neutral section.

Now as neutral sections are passed in a matter of seconds normally, and all the lights usually stay on, but the aircon is intentionally switched off, surely that tells us something doesn't it?  Another big clue is in the recent discussion about electric IEPs getting an auxiliary diesel engine just to support the 'hotel load' after a power failure...

Paul

I think I can help re some of the questions about air conditioning. 

The fan that blows the air through the coach takes relatively little power and is powered off the coach battery.  If the battery is fully charged before the charging supply is lost (eg engine stops, loss of power from overhead line or third rail) it can power the fan motor for several hours, thus providing air circulation in a sealed coach until the engine can be restarted, passengers moved to another coach etc. 

However, heating or cooling the blown air takes much more power, and more than can be provided by battery.  So this power is taken from the engine (mechanically and/or electrically) or overhead line etc depending on the type of train.  So if this power is lost, the heating or cooling will stop immediately.  However, the fan motor will continue to blow air into the coach.  Going through a neutral section in 10 seconds or whatever would have no noticeable effect on the temperature of the air being blown into the coach. 

The heat exchanger for the air-con (usually underneath the coach) has a fan to push air through it, so can function OK even if the train is stopped. 

edit: add (usually underneath the coach)

(why doesn't the 'quote' button work no longer - I just get the green 'loading' banner' and nothing happens....)

Not sure it does, does it? You board roughly 10 mins from leaving (at the earliest generally) and its working within minutes once moving. I can think of far better things to spend money on that permanent aircon.

Also, just to clarify the situation should an engine not be working on a Class 180 in service, there is a cross-feed facility which automatically gets electrical power (including for the air-con) from an adjacent carriage.  That's unlike the Turbo units which have no cross feed.