158’s with no air conditioning

[Mikey C]

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)

Surely replacing an existing system - i.e. ripping out the old system and starting afresh - would be possible, given the will to do it.

After all the 165s are basically the same age as the 158s, so it's not as if the 165s had a longer expected life than the 158s when the work was done

 

[DanNCL]

The Northern 158s I've had over the last few weeks have all had the air conditioning working fantastically.

 

[Bletchleyite]

Does the Chiltern 16x solution fit on a 158?

I don't know but I'm sure it could be modified to. There are enough 158s across the country to make it worthwhile and they pretty much all need it.

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)

It wouldn't necessarily be easier, because you can just ignore what's there, treating it as a non-fitted unit, and fit afresh.

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.

Yes, that would be best.

 

[wobman]

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

The 175's can't go on certain routes and traincrew depots don't sign them, things are never that simple on the railways.

 

[wobman]

TFW have a dilemma to leave the 158's as they are until the 197's come into service, thus saving the cost of refurbishment or replacement. Or spend a lot of money and take units out of service only to get rid of the 158's by 2022/3 once the 197's are all in service. The 158's have always had bad air con but wouldn't painting the 158's roofs white help, I remember the old pre refurb ginster 158 seemed cooler in the summer with its silver roof.

 

[edwin_m]

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.

I think the problem here is that there may not be enough space to do that.

The existing kit is distributed around each vehicle as mentioned, being connected by said pipework. To eliminate that pipework everything really needs to be in a single module. The solution used on 170s and road coaches, putting everything into a swappable roof-mounted module, won't really work on 158s because it would need huge holes cutting into the roof and almost certainly weaken the structure. The existing equipment is probably surrounded by other bits of equipment that nobody would want to touch, so it's likely that no single space is big enough for everything. Another constraint is that I believe the aircon is operated by a driveshaft from the engine and the alternator isn't powerful enough to put an electrically-driven system somewhere the driveshaft can't reach it.

So the only viable solution might be to replace equipment in the existing positions, involving the difficult job of stripping out and inserting new pipework, with the risk that the replacement suffers similar problems after a few years.

 

[43096]

I don't know but I'm sure it could be modified to. There are enough 158s across the country to make it worthwhile and they pretty much all need it.

I’m intrigued on what basis you think it is do-able.

 

[banjo125]

I've been on 158's with very good air con, that have a hopper window open & that affects the ability of the system to cool, as plenty of warm air coming in the open window (a classic case of not helping the system), although I have been on some very warm ones where the hopper windows open provide some air flow, although it is still very warm inside

 

[Llama]

The Aircon on 158s is powered by a hydrostatic pump from the engine - the same pump also drives the main alternator which has nothing to do with the air con. A separate hydrostatic pump, also on the engine, drives the radiator fan when necessary.

As I understand it the 'air con module' under the solebar driven by the hydro pump supplies 3-phase AC to both air con modules up in the ceiling, it's definitely not the case that the compressors are driven by a drive shaft from the engine like they are on a car.

 

[edwin_m]

The Aircon on 158s is powered by a hydrostatic pump from the engine - the same pump also drives the main alternator which has nothing to do with the air con. A separate hydrostatic pump, also on the engine, drives the radiator fan when necessary.

As I understand it the 'air con module' under the solebar driven by the hydro pump supplies 3-phase AC to both air con modules up in the ceiling, it's definitely not the case that the compressors are driven by a drive shaft from the engine like they are on a car.

Thanks for the information. I guess this means that if the system was re-done then there would need to be hydraulic connections from the pump to wherever the equipment was re-located, or for an electric system the alternator might have to be replaced which might mean replacing the pump as well.

 

[tomuk]

What needs to be done is to rip out the whole hydrostatic system and replace with a larger 3 phase alternator that can drive the aircon, rad fan etc electrically and an integrated roof module in place of the existing evaporator.
This would still be marginal as the hp of the engine isn't really enough for all the auxiliaries. In reality the 158s really should have had a MLU about ten years ago replacing the engine\gearbox and aircon with 172 like components.

 

[edwin_m]

What needs to be done is to rip out the whole hydrostatic system and replace with a larger 3 phase alternator that can drive the aircon, rad fan etc electrically and an integrated roof module in place of the existing evaporator.
This would still be marginal as the hp of the engine isn't really enough for all the auxiliaries. In reality the 158s really should have had a MLU about ten years ago replacing the engine\gearbox and aircon with 172 like components.

You should get the new engine and transmission under a 158, it's been done on at least one prototype, but cutting a large hole in each end of the roof of a 30yr-old load-bearing aluminium structure (and I think the 172 has a third, smaller, one for the cab too) could be prohibitive. Unless the well that the evaporator sits in is big enough for a 172-style module?

 

[Bletchleyite]

You should get the new engine and transmission under a 158, it's been done on at least one prototype, but cutting a large hole in each end of the roof of a 30yr-old load-bearing aluminium structure (and I think the 172 has a third, smaller, one for the cab too) could be prohibitive. Unless the well that the evaporator sits in is big enough for a 172-style module?

It could perhaps be put inside the passenger compartment as the Chiltern kit is.

 

[edwin_m]

It could perhaps be put inside the passenger compartment as the Chiltern kit is.

But then it wouldn't be one lift-out module unless there was also a hole in the roof big enough to lift it out, or it could somehow be manhandled through a doorway.

 

[Bletchleyite]

But then it wouldn't be one lift-out module unless there was also a hole in the roof big enough to lift it out, or it could somehow be manhandled through a doorway.

True, I suppose everything is a tradeoff. I just know the Chiltern system has been very successful with failures very rare. They were confident enough in it to remove the opening windows!

 

[Bikeman78]

True, I suppose everything is a tradeoff. I just know the Chiltern system has been very successful with failures very rare. They were confident enough in it to remove the opening windows!

How have the Chiltern 165s coped this week? I've not been on one for a few years but I agree that it worked well then, even in hot weather.

 

[tomuk]

True, I suppose everything is a tradeoff. I just know the Chiltern system has been very successful with failures very rare. They were confident enough in it to remove the opening windows!

The Chiltern system is basically a split system you would buy of the shelf for your house sat in a box on the luggage rack. It is very much a MacGyver/Heath Robinson setup which works surprisingly well. I suppose it just proves the KISS principle.

 

[edwin_m]

The Chiltern system is basically a split system you would buy of the shelf for your house sat in a box on the luggage rack. It is very much a MacGyver/Heath Robinson setup which works surprisingly well. I suppose it just proves the KISS principle.

Does this mean there is no exterior ventilation, recirculation only?

 

[Domh245]

Does this mean there is no exterior ventilation, recirculation only?

It'd be surprising if that was the case. Doing a 'roof survey' it looks like there's 4 systems that have been installed - each with two holes on the roof (and a pair on the side), so it certainly looks like there's some degree of fresh air, even I don't know which way around it is. If I had to guess, the smaller one looks to be for the condenser of the AC system (it only needs the one, and you can even see the fan in some of them!), leaving the larger grille for air transfer. I would guess(/hope) extract on the roof given they're right in the firing line for the exhaust, with fresh air via the grilles on the side of the train.

 

[Grumpy Git]

Does this mean there is no exterior ventilation, recirculation only?

Not possible, you need to get rid of the excess heat outside.

 

[Domh245]

Not possible, you need to get rid of the excess heat outside.

With a conventional "split" system, the heat is sent outside via a pair of tubes containing refrigerant, there's no air exchange involved.

 

[Grumpy Git]

I think we are talking at cross purposes here.

 

[Domh245]

I think we are talking at cross purposes here.

The original post questions was questioning whether there was a exterior ventilation (read: fresh air supply) - whilst not the case in this situation, it is entirely possible to have air conditioning without any proper ventilation, and this is how it's often done in most situations, especially where "split" air conditioning units are used

 

[superkev]

Perhaps spmeone in the know could write a sumery of the 158s air con alterations over the years which have varying degrees of sucess. Northen 158 have Lieber controls, not sure about other tocs and important hardware.
These are in order of imporatance/ unreliability are condensers, condenser fans, compressors, evaporators and supplyvair fans.
Also on a 158 where are the heat rejection condensers with there many easily clogged fins. Hope there not underneath.
Kev

 

[tomuk]

Perhaps spmeone in the know could write a sumery of the 158s air con alterations over the years which have varying degrees of sucess. Northen 158 have Lieber controls, not sure about other tocs and important hardware.
These are in order of imporatance/ unreliability are condensers, condenser fans, compressors, evaporators and supplyvair fans.
Also on a 158 where are the heat rejection condensers with there many easily clogged fins. Hope there not underneath.
Kev

AFAIK there have been three systems fitted to 158s. The original system was dual sourced by BR so half the 158s half had a different but very similar system. These were Temperature Ltd and EBAC. They have the compressor and condenser mounted under the train with evaporator above the vestibule connected by long refrigerant lines. Over the years these systems have had various mods first to R134a due to CFC ban plus other 'reliability' mods. Still pretty rubbish.

The third system is the Liebherr system which was fitted by some operators to try and fix the ongoing issues. The compressor condenser and evaporator above the vestibule with electrical power supplied from a module under the floor powered by the hydrostatic system. This is the best system but still underperforms due to lack of engine power and being a retrofit.

 

[185143]

I was on SWR 158888 earlier and it was cold inside. Not just cool, actually cold.

Then again I'd just got off a GWR 166 which was that hot onboard it actually felt pleasant to alight into the 30° heat!

 

[gallafent]

Then again I'd just got off a GWR 166 which was that hot onboard it actually felt pleasant to alight into the 30° heat!

… good to know that repainting them repeatedly is still considered more important than making the air-con work. Sigh.

 

[superkev]

AFAIK there have been three systems fitted to 158s. The original system was dual sourced by BR so half the 158s half had a different but very similar system. These were Temperature Ltd and EBAC. They have the compressor and condenser mounted under the train with evaporator above the vestibule connected by long refrigerant lines. Over the years these systems have had various mods first to R134a due to CFC ban plus other 'reliability' mods. Still pretty rubbish.

The third system is the Liebherr system which was fitted by some operators to try and fix the ongoing issues. The compressor condenser and evaporator above the vestibule with electrical power supplied from a module under the floor powered by the hydrostatic system. This is the best system but still underperforms due to lack of engine power and being a retrofit.

Thankyou. Most interesting. Now i know why I used to be boiled alive in hot weather.
Having the condenser and evoporator above the vestibule does not sound to encurage essential regular cleaning.
Do all operators now have the same system? Is there just one system per car?
Kev

 

[43096]

AFAIK there have been three systems fitted to 158s. The original system was dual sourced by BR so half the 158s half had a different but very similar system. These were Temperature Ltd and EBAC. They have the compressor and condenser mounted under the train with evaporator above the vestibule connected by long refrigerant lines. Over the years these systems have had various mods first to R134a due to CFC ban plus other 'reliability' mods. Still pretty rubbish.

The third system is the Liebherr system which was fitted by some operators to try and fix the ongoing issues. The compressor condenser and evaporator above the vestibule with electrical power supplied from a module under the floor powered by the hydrostatic system. This is the best system but still underperforms due to lack of engine power and being a retrofit.

Part of the problem is that R134a refrigerant is less efficient than its predecessor, which means the system has to work harder.

 

[Llama]

Thanks for the information. I guess this means that if the system was re-done then there would need to be hydraulic connections from the pump to wherever the equipment was re-located, or for an electric system the alternator might have to be replaced which might mean replacing the pump as well.

I probably wasn't very clear - the engines on 158s (all permutations) drive two hydrostatic pumps. One of those is an axial plunger and drives the radiator fan, the other is a variable displacement one that drives the main alternator (output rectified to 24v DC) and also drives the 'air con module' underneath the solebar (aft of the start batteries on the right side of the vehicle). As I understand it this underslung 'air con module' contains another alternator that provides a three phase AC supply to the two roof mounted air con units on each 158 vehicle, one above each door vestibule. So the actual air con system on 158s is effectively electrically powered.