Northern 158 air-con still not working in hot weather

[superkev]

With yesterdays belated hot weather I tought it would be a shame not to have the annual bash at Northerns boil you alive 158s.
Watching the world go by at sowerby bridge yesterday I didn't see a single 158 with its emergency ventilators shut so that's likely none with air con working. A poor show really and passengers deserve better.
My view is as in previous years is that maintaining it is Northerns lowest priority.
Sad that something with just 4 major components still doesn't work reliably after 20 years.
Myself, and I suspect I'm not unique, always use my car in hot weather.
K

 

[cactustwirly]

With yesterdays belated hot weather I tought it would be a shame not to have the annual bash at Northerns boil you alive 158s.
Watching the world go by at sowerby bridge yesterday I didn't see a single 158 with its emergency ventilators shut so that's likely none with air con working. A poor show really and passengers deserve better.
My view is as in previous years is that maintaining it is Northerns lowest priority.
Sad that something with just 4 major components still doesn't work reliably after 20 years.
Myself, and I suspect I'm not unique, always use my car in hot weather.
K

The Eurofima wagon in Italy I used on Wednesday, had Aircon that worked an absolute treat, especially as it was older than a 158 (I think?)

 

[superkev]

The Eurofima wagon in Italy I used on Wednesday, had Aircon that worked an absolute treat, especially as it was older than a 158 (I think?)

Yes, I wonder how French trains are coping with the 45deg temps over there.
K

 

[Polarbear]

Air con on 158’s has never been their strong point.

 

[JohnMcL7]

Air con on 158’s has never been their strong point.

I didn't realise until I'd read it here that they actually had air conditioning.

 

[Polarbear]

I didn't realise until I'd read it here that they actually had air conditioning.

Understandable! To be fair, they do have air con & when it works, it can be reasonably effective. Trouble is that it doesn’t take much for it to keel over.

 

[3141]

The guard on the Class 159 forming the 11.20 from Overton to London Waterloo yesterday announced that the air conditioning was working in two of the three carriages.

In very hot weather, guards on the SWR West of England line sometimes open all the windows that can be opened, so a train with windows open doesn't mean its air conditioning has failed.

 

[scotraildriver]

Opening the windows on a unit with working air con causes further problems, as the saloon temp sensor is just above the opening window. The cool air rushes in, the sensor thinks it cold and puts the heating on! I often see our Scotrail units running about with windows open yet the air con is working fine. Guards tend to board a unit thats been shut down thus very warm, and given their almost 30 year experience with duff air con they assume its broken and open the windows. I've lost count of the number of times I've reset the aircon, shut the windows (to a few strange looks from melting passengers) then 20 minutes later its lovely and cool.

 

[northernchris]

With yesterdays belated hot weather I tought it would be a shame not to have the annual bash at Northerns boil you alive 158s.
Watching the world go by at sowerby bridge yesterday I didn't see a single 158 with its emergency ventilators shut so that's likely none with air con working. A poor show really and passengers deserve better.
My view is as in previous years is that maintaining it is Northerns lowest priority.
Sad that something with just 4 major components still doesn't work reliably after 20 years.
Myself, and I suspect I'm not unique, always use my car in hot weather.
K

It isn't great, but given Northern's unit shortages (I suspect the cancellation rate hit double figures in West Yorkshire yesterday due 'to more trains than usual needing repairs') I hope they are using every available unit, and failed aircon shouldn't be a reason to fail a unit that has the emergency windows. I've seen quite a few tweets yesterday regarding failed aircon on LNER services where it must have been unbearable

 

[DimTim]

17:35 Bridlington - Sheffield Class 170 turbostar had 1 of 3 coaches without Aircon. Rammed until Hull.

 

[Bletchleyite]

The system plain doesn't work on Class 158s as it was designed for CFCs, modern refrigerants don't work properly as they, while safer for the ozone layer, are not as effective.

As with Class 16x which suffer a similar problem, the only fix is replacement of the air conditioning system with a completely new one. The system on the Chiltern 165s works just fine, so that would be a good choice.

 

[Non Multi]

The system plain doesn't work on Class 158s as it was designed for CFCs, modern refrigerants don't work properly as they, while safer for the ozone layer, are not as effective.

As with Class 16x which suffer a similar problem, the only fix is replacement of the air conditioning system with a completely new one. The system on the Chiltern 165s works just fine, so that would be a good choice.

The 165s (on GWR and CR) have retrofit air cooling, not air con.

 

[Llama]

The system plain doesn't work on Class 158s as it was designed for CFCs, modern refrigerants don't work properly as they, while safer for the ozone layer, are not as effective.

As with Class 16x which suffer a similar problem, the only fix is replacement of the air conditioning system with a completely new one. The system on the Chiltern 165s works just fine, so that would be a good choice.

The air conditioning systems on all Northern's 158s was replaced with a completely new Liebherr system 10-12 years ago, it worked fine.

Lack of training of traincrew is a big issue in reliability of air con on the 158s - don't force the engines to shut down with the air con running, don't open the hopper windows unless the air con is in the correct mode or isolated.

 

[superkev]

I didn't realise until I'd read it here that they actually had air conditioning.

Strictly speaking it's air cooling rather than air conditioning and is also known in building circles as comfort cooling. Proper air conditioning controls the humidity as well as the temperature.
In my previous life in computer centres the temperature was kept 20deg plus or minus 1 and the humidity 50% plus or minus 5%. Heat rejection unit fins where cleaned over the winter and refrigerant topped up ready for the summer. What a contrast to Northern rail when it seems to give in as soon as the sun shines.
K

 

[sportzbar]

I would say this is more to do with crew training to be fair. When doing my training on the 158 I had a really good trainer who talked us through the aircon on them. Actually very simple to use and in all my time of working them i have never had a problem. Most of my colleagues have never been shown how to start/reset/check the aircon so presume it is broken and just open the windows.

 

[LowLevel]

If you're talking outside temperatures of over 30 degrees it will overload and die after a while no matter how good it is. It's not designed to cope with that kind of workload.

Saturday was hot enough to cause even a healthy 158 ACU to trip out and fail intermittently. The key is managing it effectively and not taking counter productive actions like opening the windows while it's still pumping.

 

[sportzbar]

LowLevel I agree with you 100%. It is all about managing the systen and not opening the windows at the first sign of trouble. I was taught how to manage it but unfortunately most of my colleagues weren't

 

[whhistle]

The Eurofima wagon in Italy I used on Wednesday, had Aircon that worked an absolute treat, especially as it was older than a 158 (I think?)

I suspect, as Italy is significantly hotter than the UK at most times of the year, their trains have pretty much always had air con.

 

[Bletchleyite]

The 165s (on GWR and CR) have retrofit air cooling, not air con.

For the purposes of keeping passengers cool it doesn't overly matter which it is provided it works. The Chiltern system works, the 158 system does not.

I didn't know it tripped out at 30 degrees. That's just poor design, you wouldn't expect it to trip out, simply that it would carry on working but at a higher saloon temperature. Your fridge doesn't trip out on a hot day, and all aircon is is effectively a large fridge.

 

[LowLevel]

For the purposes of keeping passengers cool it doesn't overly matter which it is provided it works. The Chiltern system works, the 158 system does not.

I didn't know it tripped out at 30 degrees. That's just poor design, you wouldn't expect it to trip out, simply that it would carry on working but at a higher saloon temperature. Your fridge doesn't trip out on a hot day, and all aircon is is effectively a large fridge.

It doesn't trip out as such at 30 degrees but working way over design spec it overloads once you get to that sort of area and shows up a high pressure fault on the control system. Once it's had time to cool down it kicks back in again.

 

[Bletchleyite]

It doesn't trip out as such at 30 degrees but working way over design spec it overloads once you get to that sort of area and shows up a high pressure fault on the control system. Once it's had time to cool down it kicks back in again.

I see. Still poor design given that even in 1995 30+ degree days in summer were not exactly unknown. As I noted, a better design would be for it to continue to work but at a lower efficacy, i.e. to lower the cabin temperature but not by the full amount specified.

 

[cactustwirly]

I suspect, as Italy is significantly hotter than the UK at most times of the year, their trains have pretty much always had air con.

Being pedantic, it was an Austrian coach (Munich - Verona/Venice Eurocity train)

 

[supervc-10]

I've asked before and got nowhere, but what is the actual technical difference between air cooling and air conditioning? An AC unit has 4 basic components- a compressor pump, a valve, and 2 heat exchangers (the condenser and the evaporator). How does that differ in the air cooling units some trains have?

 

[Bletchleyite]

I've asked before and got nowhere, but what is the actual technical difference between air cooling and air conditioning? An AC unit has 4 basic components- a compressor pump, a valve, and 2 heat exchangers (the condenser and the evaporator). How does that differ in the air cooling units some trains have?

Air cooling doesn't specifically control humidity, aircon does. You've then got climate control which outputs air at a specified temperature and humidity - no trains have this, they achieve a mix by putting cold air in at the top and cooking your ankles with an electric radiator.

There are two ways you can achieve air cooling - one is aircon (a fridge, basically). The other is evaporative cooling, which involves blowing air over water and cooling as the water evaporates. This is how cheaper domestic units do it, and that actually increases humidity. I don't know if any trains use this approach but I doubt it as the liquid moving around would cause issues.

I suspect the units at some Tube stations probably use evaporative cooling, as it's easier to get water (at any temperature) to the unit than to dissipate heat.

 

[supervc-10]

Thank you @Blethleyite
So the technical difference between an Air Conditioning unit like in the 158 and the Chiltern 165 Air Cooling is that humidity is basically just ignored from a system point of view? Because conventional AC will reduce humidity, as cold air can carry less water vapour. The water vapour in the air condenses on the outside of the condensing coils and drips down. This is why in most modern cars turning the ventilation to the demister setting will turn on the AC- the humid air inside the car is dehumidified and you can see where you're going quicker! The dripping is also why if the drain out the bottom of the car gets clogged, you end up with wet patches in the front footwells.

Does the difference primarily result in the AC system constantly running on a 158, in order to dehumidify the air, with the electrical heating working to keep the temperature at a comfortable level, while in a 165 the AC system only runs when needed?

Edit: I'm also waiting on delivery of an evaporative cooler! It was only £17 on eBay, and given how warm my house can be in the summer I thought I'd give it a try! Plus, my boyfriend is American and so used to icy bedrooms, and protests at sweaty conditions!

 

[Bletchleyite]

Does the difference primarily result in the AC system constantly running on a 158, in order to dehumidify the air, with the electrical heating working to keep the temperature at a comfortable level, while in a 165 the AC system only runs when needed?

No, they both work on a "cold at the top, hot at the bottom" type basis, though it is possible to turn one of them off e.g. the heat in summer and the cold in winter. I don't think any train has climate control (i.e. the injection of air at the correct temperature) except the very unusual case of the Caledonian Sleeper Mk2 seated coaches (and only those ones).

Cars are mostly the same - with the aircon on they cool the air first then reheat it via the heater matrix, though those with climate control control this electronically to give a precise temperature of output. With a car you can similarly turn one of the two off if it isn't needed.

 

[Parallel]

Both GWR and TfW have had a lot of 158s running around with the hopper windows open within the last week or so. Really should be some major work to sort this once the PRM deadline has gone, especially as none are expected to be completely retired any time soon.

GWR’s 166s are just as bad.

 

[superkev]

I've asked before and got nowhere, but what is the actual technical difference between air cooling and air conditioning? An AC unit has 4 basic components- a compressor pump, a valve, and 2 heat exchangers (the condenser and the evaporator). How does that differ in the air cooling units some trains have?

Here goes.
As you said an air cooling or comfort cooling in the building trade has a compressor to compress refrigerant into a hot gas at around 200psi. It then passes through a finned coil (the condenser) which condenses the hot gas to a warm still high pressure liquid. This liquid is allowed to flash back to a gas by passing through a small adjustable oriface (the expansion valve) where like with an aerosol can it becomes very cold.
This cold gas passes through another finned coil (the evaporator) where it removes heat from the interior before passing back to the compressor. Steps need to be taken to ensure any compressor lub oil which gets around the system returns to the compressor which is why systems need to shut down properly after they are go off (pump down). Not allowing this will eventually destroy the system (guards and shunters take note).
Cooling the air on this way extracts moisture but as the air is cooler its humidity goes up sometimes to 100%.
Full air conditioning can control humidity by either adding moisture with a kettle like bottle or be overcooling to remove moisture then reheating it to get the required conditions. Both these processes consume a lot of energy and I dont think any trains or road vehicles do this - the full monty.
Having correctly sized coils, keeping them clean with working fans, particularly the externally mounted condensers is very important.
Hope that helps.
Kev

 

[supervc-10]

Thank you Kev! Does this mean that there is no fundamental difference between a 165 Air Cooling system and the 'AC' system on any other unit? My suspicion is that the answer is no.

Cars BTW will do the humidity control- cooling the air to remove humidity and then warming it back up again, in order to demist the windscreen.

What you say about humidity going up to 100% is often seen on aircraft in warm, humid locations during boarding, I've personally seen it in places such as Barcelona, Nice, and Rome, and the worst I've seen was in Nashville, Tennessee.

And yes- as with anything involving heating and cooling, cleanliness is very important.

 

[stj]

Have the same problem at work in our Offices, staff open the windows in warm weather and look at me stupid
when asking them to close them to let the AC do its job.AC fitted trains should not have opening windows as its an excuse not to maintain/operate the AC.Lucky that most trains have sealed windows.