Highest temp train air con can cope with

[amarshe]

I seem to remember reading mk3 air con would start to become ineffective when the outside temp went above around 30 degrees.

158 air con is legendary for its ineffectiveness due to the refrigerants…

What is the operating max temp for modern rolling stock in the UK? And will it cope with next weeks high temperatures?

 

[dmncf]

I travelled on unhealthily hot Avanti class 390s last Friday and Sunday. For those trains, the answer to your last question is no.

 

[skyhigh]

158 air con is legendary for its ineffectiveness due to the refrigerants…

That's a bit of an urban myth. Lots of the equipment is of upgraded spec. The issue is the long pipe runs in a flexible body that cause pinhole leaks which are a nightmare to find and fix. Added to underpowered systems it's a bit of a recipe for disaster. They would be just as bad with the original refrigerant.

 

[Wolfie]

I travelled on unhealthily hot Avanti class 390s last Friday and Sunday. For those trains, the answer to your last question is no.

Given the Italian origins of those trains that is a concern.

 

[DarloRich]

I travelled on unhealthily hot Avanti class 390s last Friday and Sunday. For those trains, the answer to your last question is no.

I have found that the best air con location on the pendolino is the vestibule!

 

[43096]

That's a bit of an urban myth. Lots of the equipment is of upgraded spec. The issue is the long pipe runs in a flexible body that cause pinhole leaks which are a nightmare to find and fix. Added to underpowered systems it's a bit of a recipe for disaster. They would be just as bad with the original refrigerant.

The refrigerants are not an "urban myth" though. The change of refrigerants resulting from the banning of R22 (I think it was) as it was an ozone depleting chemical saw newere types used - but these are less efficient (i.e. aren't as good at transferring heat) than the original type. Ask any AC engineer and they'll tell you!

Given the limited power available in a 158 for the aircon system, and add less efficient refrigerant and it is part of the explanation as to why the 158 air conditioning is less effective that it might be. There's various other factors involved including system maintenance, the pipe runs and crews who open the windows before giving the system a chance to work...

 

[dmncf]

I have found that the best air con location on the pendolino is the vestibule!

Definitely - on the Friday train, people were taking turns in the vestibule. The air con vent next to the accessible toilet was so refreshing, you could have branded it as Standard Premium! It was the 16:30 Euston to Glasgow and the guard arranged a train set swap at Crewe because too many carriages had overheated. The Sunday return train had some bearable carriages and simply continued to Euston.

 

[DarloRich]

Definitely - on the Friday train, people were taking turns in the vestibule. The air con vent next to the accessible toilet was so refreshing, you could have branded it as Standard Premium! It was the 16:30 Euston to Glasgow and the guard arranged a train set swap at Crewe because too many carriages had overheated. The Sunday return train had some bearable carriages and simply continued to Euston.

Whereas on xc standing next to the accessible toilet results in you breathing in anothers pooh fumes for 3 hours

 

[matacaster]

I seem to remember reading mk3 air con would start to become ineffective when the outside temp went above around 30 degrees.

158 air con is legendary for its ineffectiveness due to the refrigerants…

What is the operating max temp for modern rolling stock in the UK? And will it cope with next weeks high temperatures?

158 air conditioning is also very unreliable, often only working in winter!

 

[AM9]

The refrigerants are not an "urban myth" though. The change of refrigerants resulting from the banning of R22 (I think it was) as it was an ozone depleting chemical saw newere types used - but these are less efficient (i.e. aren't as good at transferring heat) than the original type. Ask any AC engineer and they'll tell you!

Given the limited power available in a 158 for the aircon system, and add less efficient refrigerant and it is part of the explanation as to why the 158 air conditioning is less effective that it might be. There's various other factors involved including system maintenance, the pipe runs and crews who open the windows before giving the system a chance to work...

Not sure what the replacement refrigerant is but less dirty offerings such as R410A tend to need much a higher pressure to operate, which might reveal the weaknesses of older piping quicker.

 

[ainsworth74]

I'm not sure what the maximum temperature is but I've usually found 185s have extremely good aircon. Paradise on a boiling hot day.

 

[TT-ONR-NRN]

I’ve never known anything so refreshing while travelling, than getting off an oven-esque 455 at New Malden and transferring to an ex-Shepperton 707 for the rest of the journey to Vauxhall. The 707 was like a fridge. The cold air just hit you when walking on.

Walking off the train was more like when you land somewhere exotic and walk off the plane steps, and the heat just hits you. Only it’s less exciting and more of an irritation when in Vauxhall, compared to Barbados.

 

[Jamesrob637]

185s and most other Desiro are good. ICE in Germany are excellent too, as are most TGV.

My Skoda Superb is good too

 

[Skie]

390's can be a mixed bag in extremes when the heat lasts a good number of days. In 2019 they almost all had one or two coaches fail in a set, which on a lighter loading isnt so bad but can cause issues on the more rammed trips. But when it's working, they do a great job of keeping cool.

 

[sw1ller]

Was sat on a 175 last week from Shrewsbury on a very hot day and had to put my jacket on. They’re not always like that though.

 

[Razorblades]

Two points:

Every new build train spec I've dealt with since Class 166 in 1992 has had a working temperature range for its aircon stipulated in the contract. This is within the overall operating spec for the train itself. I would need to delve into the archive to get one such spec out to interrogate, but from memory the trains have to be able to operate in conditions ranging from -20C to +40C, or thereabouts. That's not to say that certain on-board functions have to operate in un-degraded mode across this whole range.

Second: with a large quantity of fleets now provided under Train Service Agreements, it will be interesting to see quite what redress TOCs could seek from their service providers should equipment fail to deliver, on trains offered for service during the heatwave, as the performance KPIs are challenged.

 

[Grecian 1998]

I'm not sure what the maximum temperature is but I've usually found 185s have extremely good aircon. Paradise on a boiling hot day.

444s generally have very effective air con too - must be a family thing. It's noisy but effective (and given how many people feel headphones are optional, noisy is no bad thing anyway).

Parts of Germany can get very hot and or humid in summer, more so than here (pretty much anywhere away from the coast) so you would expect Siemens to be able to install effective air con TBF.

 

[Ken H]

444s generally have very effective air con too - must be a family thing. It's noisy but effective (and given how many people feel headphones are optional, noisy is no bad thing anyway).

Parts of Germany can get very hot and or humid in summer, more so than here (pretty much anywhere away from the coast) so you would expect Siemens to be able to install effective air con TBF.

Humidity is an important factor. It can make a warm day feel very unpleasant.
But when you cool air it will cause condensation. I assume the water is dumped on the track. Its clean so no risk.
But aircon feels nice because it reduces the water content of air allowing sweat to evaporate causing cooling of the skin. Which is what sweat is for, of course..

 

[superkev]

My experience with building air con in the early 1990s was that the uk outside design temp was often around 27deg (its hopefully much higher now). Above this performance becomes reduced. At higher temperatures the heat rejection equipment, usually on the roof, cannot get rid of the heat. This results in safety shut downs when refridgerant pressure reaches around 400psi. Sounds a bit like 158 aircon.
Its very important in summer to keep the fins on heat rejection equipment clean as efficiency soon degrades.
I suspect train air con cleaning is not a high priority on the uk railways.
I remember hosing the condensers down in hot weather with water to keep things going.
Another thing I learnt back then was only buy Japanese kit as it just ran and ran.

May be of interest.
Kev

 

[philosopher]

Two points:

Every new build train spec I've dealt with since Class 166 in 1992 has had a working temperature range for its aircon stipulated in the contract. This is within the overall operating spec for the train itself. I would need to delve into the archive to get one such spec out to interrogate, but from memory the trains have to be able to operate in conditions ranging from -20C to +40C, or thereabouts. That's not to say that certain on-board functions have to operate in un-degraded mode across this whole range.

Second: with a large quantity of fleets now provided under Train Service Agreements, it will be interesting to see quite what redress TOCs could seek from their service providers should equipment fail to deliver, on trains offered for service during the heatwave, as the performance KPIs are challenged.

Generally I find air conditioning on trains in the UK to be pretty good. I was on class 168 last Monday morning and at times it was actually quite chilly. The main exception seems to be the class 158 / 159, I was on one these last year on day when the temperature was in the high 20’s and it was definitely too hot. The crew had to give out bottles of water towards the end of the journey. I do sometimes come across a carriage were the air con has obviously failed, however in these situations you can usually sit in another carriage.

A few weeks ago I was on a Railjet train from Prague to Vienna and was seated on the side facing the sunlight. Where I was sitting it got uncomfortably warm, particularly in the second half of the journey. The temperature on that days was probably in the high twenties.

 

[greyman42]

Was sat on a 175 last week from Shrewsbury on a very hot day and had to put my jacket on. They’re not always like that though.

This is a good point. if you are travelling on a hot day without a jumper or jacket and you get on a train where the a/c is over the top, it is not very pleasant.

 

[Mordac]

I'm not sure what the maximum temperature is but I've usually found 185s have extremely good aircon. Paradise on a boiling hot day.

Generally the case with Siemens trains, and 350s are very good in that respect too.

 

[Horizon22]

My understanding is that around 30C, the systems become ineffective as they cannot handle the gradient required to cool down the stock that much, but I’m no engineer and only going on past experiences and reports from others. Not sure whether more modern stock can handle this better, but I think it’s a question of the limits of science (the capacity of the air con unit on a train) at very high temperatures rather than rolling stock engineering.

 

[Llama]

The 195s and 331s seemed to have their A/C set a couple of years ago to only allow cooling down to 7°C lower than detected outside temperature, so that's not so great for temperatures over 35°C. Although hopefully the fact the A/C should reduce the humidity as well as temperature would still help make their interiors feel more comfortable.

 

[supervc-10]

My Skoda Superb is good too

You might say that your Skoda's AC is superb!
(sorry)
I'd add as well that the system in my parent's Skoda Enyaq is even better than when they had a Superb- because with electric cars you can normally start the AC with an app before you get to the car.

I am heading up to London from Salisbury tomorrow- I'm not looking forward to it. It's going to be toasty on the 159. I might go for the 'stopper' which only goes as far as Basingstoke, and get on a Desiro from there! Definitely going to take a bottle of ice water with me from home!

I've not had any issues with most post-privatisation stock, I've never had an issue with the Pendos when I was living up in Manchester. The old 159s though....

 

[mmh]

Lots of talk about 158s, unsurprisingly, and why their aircon is so unreliable. I'm not convinced it was ever expected to be. They have an unusual feature suggesting it wasn't expected to be!

Was the 158 the first British multiple unit with aircon? I don't know, but I wouldn't be surprised if it was.

 

[thenorthern]

With air conditioning it's not so much the heat more how humid the air is. The air has to be humid for it to work. In places where it's humid like rainforests it can work very well but in places where it isn't such as the desert it's often better to use a swamp cooler.

 

[py_megapixel]

How is the AC on the Hitachi class 800 series?

I assume they fixed the problem it had on the first day causing it to fail and give some of the seats a nice soaking...

 

[Mikey C]

The retrofitted air con/cooling on the 165s is very effective, even if my experience of the GWR 165s is that the system makes a complete racket!

 

[Flying Snail]

With air conditioning it's not so much the heat more how humid the air is. The air has to be humid for it to work. In places where it's humid like rainforests it can work very well but in places where it isn't such as the desert it's often better to use a swamp cooler.

That is just complete rubbish.