158’s with no air conditioning

[Tynwald]

The HVAC on these units is a poor design. Hydrostatic driven condenser fans, and compressors. condenser on the underfame, evaporater in the roof. long refrigerant pipe runs with joints. Then the issue with controllers.

 

[Bikeman78]

Opening windows isn't a complete solution either - I once was on a Cardiff to Portsmouth 158 with the windows open (admittedly they don't all open, but I don't think adding more would have made much difference) which was eventually terminated short at Westbury due to the heat. On the rare occasions we got up to speed the open windows were helping, but most of the time we were crawling along and the open windows were having virtually no effect. If it's this hot, I would expect Temporary Speed Restrictions (I'm guessing that's why my aborted train was going so slow, but I don't know for sure) to be in force in many areas meaning the driver cannot get the speed up to make the open windows effective.

I've just been on two Northern 156s. Outside temperature 24 degrees, saloon temperature was pleasant with all windows open. Same temperature around Dundee and Aberdeen on Friday and the 158 saloons were far too warm. Obviously if the temperature got up to 30 like it is in Wales at the moment then a 156 would be awful too.

 

[DB]

I would completely disagree that the 158s are awful units; the air-con on them is (frequently) awful but other than that they are decent units.

Agree - they are fine most of the time - just best avoided if possible in hot weather!

 

[skyhigh]

The HVAC on these units is a poor design. Hydrostatic driven condenser fans, and compressors. condenser on the underfame, evaporater in the roof. long refrigerant pipe runs with joints. Then the issue with controllers.

Exactly. It's a combination of a weedy alternator, cooling capability that's easily overwhelmed and poor design (the previously mentioned pipework etc) mixed in with a bit of obsolete 90s electronics for good measure. Poor maintenance isn't really the issue here - even with a full overhaul the system will probably end up knackered again in a period measured in days rather than weeks. It's very hard to get it to work perfectly. Spare part availability also isn't really a problem. Things like pinhole leaks in the pipework are a nightmare to troubleshoot in particular. The question is do you stop the unit for x days trying to sort it - while trains are shortformed as people are packed in more tightly as a result - or run the best you can? If you stopped 158s for poor aircon you'd be stopping virtually the entire fleet on weeks like this.

The "leaky pipes" issue from body flex is interesting - 170s I guess avoid that by having two smaller self-contained packs mounted on the roof, one feeding each end of the air conduits. The other upside of that is that if one fails the other one can just about keep things tolerable.

170s have an interesting design where they have two roof mounted units forming 4 'zones' in each carriage (one in each end third past the doors, the middle section split in two). It can create a very odd situation where one part of the coach is very warm, and the rest very cool. 170 aircon isn't particularly flawless though, as an example recently we've been replacing a HVAC roof module pretty much daily to keep up with failures.

 

[Tynwald]

175/180 have a self contained dual module mounted in the roof. No refrigerant pipes outside of module. All pipe joints braised. Very rare both circuits fail, but then you change the roof module, easily done within a shift.

 

[CJSwan]

Scotrail have in the last couple of months replaced all the controllers with brand new units from Knorr Bremse. We'll see how that goes.

From my experience I’ve managed on several occasions to reset these new controls and got the on board temperatures down from 27°+ to about 20-21°, in about 15-20 minutes.

An issue seems to be that not all guards/depots have been briefed on how to do this. And also, some sets just won’t reset and you have to report, switch off and open windows.

 

[43096]

The HVAC on these units is a poor design. Hydrostatic driven condenser fans, and compressors. condenser on the underfame, evaporater in the roof. long refrigerant pipe runs with joints. Then the issue with controllers.

And then add in train crews opening the windows before the system has a chance to do its thing. That is still a big problem.

 

[61653 HTAFC]

In the past, I'd often thought that issues with the aircon on 158s were exaggerated by enthusiasts (a bit like the "ironing board" seats) but perhaps I just got lucky: in previous hot spells I'd at the very least a 50% success rate in 158s I'd boarded having aircon that was performing adequately.
Though this current hot spell is almost certainly a sign of things to come, so something really ought to be done about the 158s- as with new diesel bans coming in they're likely to be with us right up until legacy diesels are outlawed.

 

[Grumpy Git]

The cynic in me says the aircon units were a cheap solution back in the day and they fitted hoppers to reflect this?

"Underpowered and overloaded" is the phrase that springs to mind.

Any correctly designed Airton system should automatically switch off if a window is opened. You can't expect them to cool Powys.

 

[Cardiff123]

Sometimes faults cannot be repaired immediately, perhaps because parts have to be ordered etc, it has nothing to do with the quality control. A train with defective brakes would not be allowed to enter or continue in service. A train with defective air conditioning isn’t ideal but is better than cancelling a service.

Judgement calls like this are made all the time. Show me any train in service with absolutely no faults and I’ll eat my hat. Safety critical is what matters, there is nothing dubious about it at all.

I'd say with extreme heat now becoming a regular feature of our weather from anytime in late March through to September, it's time for on board temperatures & ventilation to be taken seriously as an essential health & safety threat. The Met Office today has issued it's first ever 'extreme heat' warning for most of Wales and southern & central England. How is it acceptable to knowingly put trains into passenger service without working air con and not enough openable windows during an official 'extreme heat' warning period? If this principle was applied to the 158 fleet (and some of the 175s atm), it would be grounded tonight.

Met Office issues first UK extreme heat warning

It covers south-west England and large parts of Wales as the UK experiences a prolonged hot spell.

www.bbc.co.uk

Trains are routinely stopped for other extreme weather warnings such as severe, heavy rainfall. Heat should be no different if conditions on board will be a threat to the health of vulnerable passengers.

TfW are lucky that they've got the 197s coming into service within 18 months. But it's pretty clear that if 158s are to stay in service for years to come, it's time to fit lockable hopper windows to every window on 158s, not just for emergency air con failiure, but regular, if not every day air con failiure during spring and summer.

 

[alangla]

I thought the usual chain of events with these things was:
Leave depot in the morning with it working ok & comfortable temp
Get to terminal station when it’s sunny & warm
Stop engines & leave portable greenhouse parked in the sun for a while
Start it up
Notice it’s a bit warm
Open windows almost immediately
Knacker aircon after a couple of hours of cooling the surrounding countryside
Return to depot & repeat the following day

In some ways it would seem a lot more sensible if the engines could auto-start if required for additional cooling effort, similar to the way car stop-start systems will either keep running or start up if the internal temperature is too high. No doubt that would result in complaints about units sitting smoking away at terminal stations though.

 

[61653 HTAFC]

I thought the usual chain of events with these things was:
Leave depot in the morning with it working ok & comfortable temp
Get to terminal station when it’s sunny & warm
Stop engines & leave portable greenhouse parked in the sun for a while
Start it up
Notice it’s a bit warm
Open windows almost immediately
Knacker aircon after a couple of hours of cooling the surrounding countryside
Return to depot & repeat the following day

In some ways it would seem a lot more sensible if the engines could auto-start if required for additional cooling effort, similar to the way car stop-start systems will either keep running or start up if the internal temperature is too high. No doubt that would result in complaints about units sitting smoking away at terminal stations though.

It wouldn't be viable everywhere even if it would be in some places, but one solution to that situation would be to hook the unit up to a shore supply so that the aircon can keep running even if the engines are off for a while. No idea if the systems on 158s would be able to work that way, but it should at least be looked into for new builds. Particularly if batteries are the chosen solution for self-propelled units, otherwise hot days will cut the range of units between charges.

 

[LSWR Cavalier]

Air-con is just a con.

Much better to switch it off, or not install it in the first place.

Is it worse in winter or summer? I wear more clothes in winter, then I get on a train so hot, one could wear just a vest without feeling cold.

 

[Bletchleyite]

The cynic in me says the aircon units were a cheap solution back in the day and they fitted hoppers to reflect this?

"Underpowered and overloaded" is the phrase that springs to mind.

Any correctly designed Airton system should automatically switch off if a window is opened. You can't expect them to cool Powys.

I would just expect it not to fail in those circumstances, but rather to deliver cooling to the extent it can within its capabilities without overheating or tripping out. My car aircon doesn't conk out if I open a window, and nor would I expect it to do so. A system that trips out requiring reset, or is damaged, in the event of a not unlikely scenario occurring is not fit for purpose.

Opening a window with aircon running is a waste of energy, but it absolutely should not cause it to conk out. If I leave the fridge door open, that doesn't.

Air-con is just a con.

Much better to switch it off, or not install it in the first place.

Is it worse in winter or summer? I wear more clothes in winter, then I get on a train so hot, one could wear just a vest without feeling cold.

Aircon is lovely on a day like this, and systems that work properly do exist, e.g those fitted to Desiros, and are available for retrofit, e.g. the Chiltern 165 system. Rip the old system out and fit that.

 

[WillPS]

Air-con is just a con.

Much better to switch it off, or not install it in the first place.

Is it worse in winter or summer? I wear more clothes in winter, then I get on a train so hot, one could wear just a vest without feeling cold.

Disagree strongly. I'm lay on my bed with a portable air con blasting cold dry air at me right now. Best £200 I ever spent.

I agree that winter can be uncomfortable but at least you have the option of taking those extra clothes off.

 

[skyhigh]

Air-con is just a con.

Much better to switch it off, or not install it in the first place.

Is it worse in winter or summer? I wear more clothes in winter, then I get on a train so hot, one could wear just a vest without feeling cold.

Rubbish. You try working a 150 in this heat for an 8hr shift and compare that to a unit with aircon instead.

What's a con about it...?

 

[Domh245]

I would just expect it not to fail in those circumstances, but rather to deliver cooling to the extent it can within its capabilities without overheating or tripping out. My car aircon doesn't conk out if I open a window, and nor would I expect it to do so. A system that trips out requiring reset, or is damaged, in the event of a not unlikely scenario occurring is not fit for purpose.

Opening a window with aircon running is a waste of energy, but it absolutely should not cause it to conk out. If I leave the fridge door open, that doesn't.

Given that there's only 4 tiny opening windows on a 158 (which by most accords are rubbish at getting air in, even at speed), I very much doubt that leaving windows open and running the AC are what is causing it to conk out. It won't be helping where it can't kick out enough coolth to maintain temperature, but it's highly unlikely to be the root cause of the issues, especially when there's evidence that the compressors are susceptible to damage unless shutdown in the correct (and time consuming) way. I keep seeing assertions that it's the windows that overwork the AC and knacker it, but not from anyone I recognise as an "insider" who'd be able to say with certainty that bits are failing due to overuse as opposed to a miscellany of other faults.

 

[Rhydgaled]

Is it worse in winter or summer? I wear more clothes in winter, then I get on a train so hot, one could wear just a vest without feeling cold.

The problem there is heating, not air-con, but there is an issue there. The big problem I find in winter is interchange - the train, bus and any buildings you spend time in during the day will all have heating (and that seems to be generally far more reliable than on-train air-con) so you dress for that, with perhaps one extra layer for walking from your house to the station (and the exercise of walking will help keep you warm too). But then you come to change bus/train at some windswept station with (effectively) naught for shelter. Yes there is likely to be a bus-shelter-type-thingy but sit in one of those for very long and you soon realise that the wind gets in them no trouble. If you have very long at all to wait you will soon be frozen. Wearing more clothes just means more layers to take off once on the train, and the more layers you have to take off the more likely you are to lose an item of clothing during your journey.

 

[Bletchleyite]

Given that there's only 4 tiny opening windows on a 158 (which by most accords are rubbish at getting air in, even at speed), I very much doubt that leaving windows open and running the AC are what is causing it to conk out. It won't be helping where it can't kick out enough coolth to maintain temperature, but it's highly unlikely to be the root cause of the issues, especially when there's evidence that the compressors are susceptible to damage unless shutdown in the correct (and time consuming) way. I keep seeing assertions that it's the windows that overwork the AC and knacker it, but not from anyone I recognise as an "insider" who'd be able to say with certainty that bits are failing due to overuse as opposed to a miscellany of other faults.

Yes, I've seen the sticker on the units stating that the aircon unit will be damaged if not shut down correctly, and I can't think of any other response to that than "what an incredibly stupid piece of design". At least it isn't going to kill anyone in the way the 737 Max did*, but it's in a similar area of "designing stuff with counterintuitive procedures for use", which is nothing short of an incredibly stupid idea if you want them to keep working in the challenging environment of a railway.

* Or PCs etc with unbuffered I/O ports years ago, where you could fry it by plugging/unplugging stuff with the power on.

 

[Domh245]

Yes, I've seen the sticker on the units stating that the aircon unit will be damaged if not shut down correctly, and I can't think of any other response to that than "what an incredibly stupid piece of design". At least it isn't going to kill anyone in the way the 737 Max did*, but it's in a similar area of "designing stuff with counterintuitive procedures for use", which is nothing short of an incredibly stupid idea if you want them to keep working in the challenging environment of a railway.

* Or PCs etc with unbuffered I/O ports years ago, where you could fry it by plugging/unplugging stuff with the power on.

It's not an ideal bit of design, but given the necessary design compromises (particularly the need to site the compressor below the solebar), and the fact that there is a procedure in place, the non-following of it is the issue, not the design. Intuivity doesn't really matter if you've been briefed what the procedure is, though I'd hope that staff get briefed on why they can't just force the engines off to avoid damaging the system

It's no different (bar scale) to shutting a PC down correctly, rather than pulling the cord out.

 

[Bletchleyite]

It's not an ideal bit of design, but given the necessary design compromises (particularly the need to site the compressor below the solebar), and the fact that there is a procedure in place, the non-following of it is the issue, not the design. Intuivity doesn't really matter if you've been briefed what the procedure is, though I'd hope that staff get briefed on why they can't just force the engines off to avoid damaging the system

It's no different (bar scale) to shutting a PC down correctly, rather than pulling the cord out.

It is quite different, because doing that to a PC doesn't damage the hardware. It used to before hard drives had automatic head parking, which was an example of designing out a vulnerability to mild misuse.

 

[DB]

It is quite different, because doing that to a PC doesn't damage the hardware. It used to before hard drives had automatic head parking, which was an example of designing out a vulnerability to mild misuse.

Well, it could do in theory, but in practice it rarely did.

 

[Bletchleyite]

Well, it could do in theory, but in practice it rarely did.

Yes, true, because people didn't turn the PC off then kick it round the room, so the head lying on a part of the drive containing data didn't really matter.

But as for 158 aircon, I maintain it's still poor design. If they have a future it needs replacing completely. The Chiltern retrofit works well, fit that.

 

[Bikeman78]

175/180 have a self contained dual module mounted in the roof. No refrigerant pipes outside of module. All pipe joints braised. Very rare both circuits fail, but then you change the roof module, easily done within a shift.

I had 175102 from Crewe to Cardiff yesterday afternoon. The air con was spot on.

 

[skyhigh]

The Chiltern retrofit works well, fit that.

Does the Chiltern 16x solution fit on a 158?

 

[gallafent]

But it's pretty clear that if 158s are to stay in service for years to come, it's time to fit lockable hopper windows to every window on 158s, not just for emergency air con failiure, but regular, if not every day air con failiure during spring and summer.

Or fix the air-con. As others have mentioned, retrofit options which are effective and reliable are clearly available and have been for some years (per Chiltern 165s et al). That would clearly be preferable to downgrading to a draughty noisy environment resembling a bus from the 1980s (or indeed a 150).

 

[Grumpy Git]

I had 175102 from Crewe to Cardiff yesterday afternoon. The air con was spot on.

Just replace the 158 with a 175, jobs a good'un.

 

[Failed Unit]

Does the Chiltern 16x solution fit on a 158?

I think Chiltern is a new system with the respect to it didn't have one in the past. Really like if someone decided to air-condition a 156. It may be easier to fit a 156 with air-condition then retro-fit a 158 with a new system (wasn't this tried on many 158s including the Scotrail and EMR ones and both TOCs still have lots of problems - you can tell if a unit was modified because the inlets on the roof look different)

 

[Rhydgaled]

I think Chiltern is a new system with the respect to it didn't have one in the past. Really like if someone decided to air-condition a 156. It may be easier to fit a 156 with air-condition then retro-fit a 158 with a new system (wasn't this tried on many 158s including the Scotrail and EMR ones and both TOCs still have lots of problems - you can tell if a unit was modified because the inlets on the roof look different)

Did the 'new' systems fitted on ScotRail, EMR etc. class 158s retain the leaky pipe work that some have said is a problem with the class 158's original system? If those posters reporting issues with pipework are correct, it sounds like a completely new system with a very different design (minimising pipework and not reusing any of the original pipes) is needed.

 

[Failed Unit]

Did the 'new' systems fitted on ScotRail, EMR etc. class 158s retain the leaky pipe work that some have said is a problem with the class 158's original system? If those posters reporting issues with pipework are correct, it sounds like a completely new system with a very different design (minimising pipework and not reusing any of the original pipes) is needed.

Which makes sense. But possibly is more difficult to do then fitting to a unit that has never had air-conditioning in the past like a 150 / 156. However I have no idea how long these units have left. Is it worth it. (Including the 158)