'S' Stock Cab Heat and Vent

[prjb]

I went to a meeting in Derby this week and one area covered was the cab heating/ventilation and air con system. We have absolutely 'mullered' this subject to death in other threads but I just thought the drivers on the forum would appreciate an update.

There will be two seperate switches for the system.

One switch has four positions and controls the air flow speed. It will be labelled:
Auto Attempts to maintain the temperature set (Low/Med/High) on the other switch automatically
Low It does what it says on the tin!
High It does what it says on the tin too!
Emergency Vent Allows a flow of fresh air into the cab with no air con

The other switch also has four positions and controls the temperature. It will be labelled:
Off Allows no air in or out and the air con is off
Low This is around 19.
Med This is around 21.
High This is around 23

You probably will remember we discussed emergency vent previously as a means of having fresh air with no air con. The concern for me is that Off allows no air flow what-so-ever. This could cause co2 emissions to build up IMHO, which is not good.

The suggestion is to remove the Emergency Vent option from the air flow control and just have it as a three position switch. Then we would make Off have the same effect as Emergency Vent. This would mean that, in Off, drivers could still enjoy fresh filtered circulated air in the cab but it would not be directed/blown in and would not be heated or cooled.

Also, we have asked BTUK to try their best to get a vent close to the driving position similar to that in a car. This would allow drivers to be able to have a limited amount of air at close quarters. I say 'limited' because BTUK think the airflow will not be huge. This is due to the amount of space available for the pipework and the force needed to send it through.

So, I dread to think what will happen now I have started a dedicated thread to this subject but I wanted to keep you guys up to date with developments. I am now moving in to an Anderson Shelter at the bottom of the garden for a few months!

[Chris M]

I'm confused about what happens when switch 1 is set to "emergency vent" and switch 2 is set to "off"?

[Deleted]

With the current design as postulated by BTUK, when the left switch is set to "Emergency Vent" and the right switch is set to "Off", there is no airflow at all.

[Deleted]

OK, have I understood this correctly?

The Low, Med and High settings control both heaters and A/C to maintain a constant cab temperature.

If the thermostat fails then we have no heater that can just be switched on to provide heat regardless?

[Chris M]

theonekea said:

With the current design as postulated by BTUK, when the left switch is set to "Emergency Vent" and the right switch is set to "Off", there is no airflow at all.

That seems rather counter-intuitive to me - if I saw "emergency vent" I would expect to get airflow regardless of the setting of any other switches.

[Deleted]

Which is no doubt why prjb has made this thread, so that he can get the 7 District drivers on this forum to tell him why they disagree with the current design. That way, he has hard data to use when he suggests that the design be changed.

[Deleted]

barney said:

Now sometimes a driver will report a 'smelly cab' and it gets put up as 'NDF' on the defect book. The smells can vary from pee to poo and be unpleasant.

That's a good point. We do get some rather strange smells in the cab sometimes, though not always bad - I picked up a train once that smelt of warm strawberry jam!

I can only assume someone had dropped some down the back of the kneespace heater, which is quite easy to do on a D stock - if you knock anything off the "table" (shoe paddle) it often comes down behind the desk and bounces off the top of the heater onto your feet.

[Deleted]

theonekea said:

Which is no doubt why prjb has made this thread, so that he can get the 7 District drivers on this forum to tell him why they disagree with the current design.

There's 8 of us AFAIK.

[Colin]

Ok, assuming I understand it correctly ( ;D ;D), if the air speed switch has only three positions as proposed, it's up to the temperature switch to control the whole system. By altering the 'off' position on the temperature control so that it allows 'outside air' to freely enter the cab - how can we stop that flow?

That sounds confusing ;D.

How can I put it.............is there a scenario whereby the system is off and there is no air entering the cab?

[Oracle]

I believe that ironically Dagenham came up with the idea for the Mark 1 Cortina for what they called "Aeroflow", with ducted fresh air taken from the front end to the dash, aimable at the driver or passenger, that had a simple open-close mechanism. My thoughts are that if you have a supply of air from the outside, you ought to have a means of closing it manually or electrically and the mechanism should be well sealed to prevent draughts.

[Colin]

I think you are reading more into my question than need be - all I'm asking is: can I have no air entering the cab if I choose?

[Chris M]

If possible I think what would work would be a very simple system
switch one: amount of air - none, low, medium, high
switch two: temperature - outside temperature (i.e. no aircon), cool, warm, hot.

[Chris M]

Hindenburg - it doesn't matter why (I'm not a fisherman and spend most of my time indoors, and I don't understand it either), but if it remains how prjb described it, then yes I think you will be able to have no air comming if that is what you want.
However, you will also be able to have outside air comming in, or air conditioned air comming in, depending on what you want - which is surely what the designers should be providing?

[agoodcuppa]

barney said:

"I think you are reading more into my question than need be - all I'm asking is: can I have no air entering the cab if I choose?"

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Now THAT I don't understand. Why on earth would someone who loves sea fishing want to cut off all the fresh air?

Because the air entering at any given moment might not be as fresh and bracing as that found 5 or 6 miles off the coast.

[Colin]

Indeed ;D ;D ;D

I like to have air entering the cab, whatever the source. But once an ambient atmostsphere is reached, I like to maintain it. Sometimes it can be better to have no hot or cold air entering the cab - for example, at dusk in summer. As the heat dies down from the sun, the air (outside the train) cools meaning the cab actually becomes comfortable with the doors closed and no heat/vent is required.

I'm not suggesting I never use any form of heat/vent - just that there are occassions when it's not needed.

[Oracle]

And also there are times that you might want heat and fresh air! Car manufacturers wokr up to this years ago but no car that I have owned has this facility. Air con has a wonderful advantage of drying out the mositure in the air, and a small car unit can distill an amazing amount of liquid water. The flip side of having dry air is that it reduces moisture as I said, and when directed at glass it can be a boon to demist the inside. Air con should be used on vehicles all year round because of lubrication of seals, etc. and prevention of bacterial and mould growth unless you then use special sprays of course.

I have to say that Colin has a fair point, and sometimes in a road vehicle you neither need air con, heat or fresh air from a comfort aspect. However there are also times when you are stuck in traffic say or in a car park where you want to turn off the incoming air intake for the air con or fresh air vents to stop being fumed. In a car or van you have a recirculating system that is a closed loop. Colin I believe is suggesting a similar idea...a shut-off. Forgive me but his suggestions have merit, or have I misdirected myself somewhere?

I myself love the sea air and fishing, used to ride motorbikes in all weathers including freezing snow, and I suppose would drive a sports car with top down in the winter.

[Colin]

The _substandard has often raised the issue of how dangerous dust levels are - and LUL has always refuted those claims, backing it up with University studies.

AFAIK tunnel cleaning does not occur - certainly not in the sense that it has in the past

[Deleted]

This all sounds a bit 1980's to me still !!! (sorry PRJB !)
(I'm not sure i fully understand it anyway !)

My car has a climate control system - I set the temperature i want (the range is 16 degrees C to 29 degrees C ) (or continuous cooling or maximum heating) and the system maintains the environment at that temperature.
It defaults to conditioning the air, regardless of temperature (don't forget proper air conditioning DOESN'T have to cool the air), and drawing the air from outside.
However this can be over ridden by push buttons, to not condition and filter the air / to recirculate from inside / to adjust the fan speed. It also has options for briefly clearing windscreens etc.

Now that is a minimum of what i expect for a train cab in the 21st century ! No wonder ASLEF are going nuts about the diabolical state of train cabs.

A seperate "passive" heat supply is also a must in my view.
And a means of maintaining a rear cab at a proper useable temperature. (if you are on the Olympia shuttle, the trains cabs have no time to warm up before you change ends again)

As to the "fresh air" discussion, like Colin, I most certainly expect an option of no drawn air and neither heating nor cooling. I spend loads of time daily closing off all the vents on D stock to prevent air being drawn from outside ! (And every stock - bus and train - i've encounteed soon has plenty of drafts (draughts ?) to send a chill wind over you )

[donnytom]

Surely the easiest thing for the drivers would be to make it like the controls in a car? Either the 'old' way of having a airflow rate controller and a temperature controller, even a direction controller, or a newer "climate control" type. Then they can choose to have-

- air from outside the cab
- air from an air-conditioning system
- recirculated air from the cab
- no air

For that matter, would it be very difficult to fit a car system to the cab of a train, as they use roughly similar volumes of air and are reasonably compact?

[Deleted]

An off the shelf pressurization / airconditioning unit from a tractor cab would probably do the job. The main obstacles to using automotive units is the lack of hot water and vacuum on an electric train. If you substitute an electric heater for the hot water matrix and use pneumatic controls instead of vacuum it would probably work.
Which leaves a question for prjb of whether LUL has ever considered using a positive pressure system in train cabs to keep out dust and fumes? This is pretty common on agricultural and construction machinery and works quite well.

[Deleted]

donnytom said:

For that matter, would it be very difficult to fit a car system to the cab of a train, as they use roughly similar volumes of air and are reasonably compact?

Is a car system designed to be used for around 18 hours a day, 364 days a year?

[prjb]

awkward42 said:

I'm confused about what happens when switch 1 is set to "emergency vent" and switch 2 is set to "off"?

It's a bl~~dy good question! I will ask, but I would imagine that emergency vent takes priority.

[prjb]

adw said:

OK, have I understood this correctly?

The Low, Med and High settings control both heaters and A/C to maintain a constant cab temperature.

If the thermostat fails then we have no heater that can just be switched on to provide heat regardless?

Yes that is correct, as the system has dual redundancy built in there is no need for traditional knee space type heaters.

[prjb]

barney said:

Now THAT has answered my main concern nicely. Drivers WILL be allowed to have some fesh air direct from atmosphere if they want it! That is extremely good news and satisfies me no end. At least each individual driver will have a choice of recycled air or fresh if they want it. BYW my main query about fresh air was this >

As you know depot staff want to get their heads down ASAP. Now sometimes a driver will report a 'smelly cab' and it gets put up as 'NDF' on the defect book. The smells can vary from pee to poo and be unpleasant. With option of allowing fresh air into the cab from atmosphere the smells are minimised. Thanks for the reassurance PJRB

Hey, I aim to please! At the end of the day you were a driver.

[prjb]

colin said:

Ok, assuming I understand it correctly ( ;D ;D), if the air speed switch has only three positions as proposed, it's up to the temperature switch to control the whole system. By altering the 'off' position on the temperature control so that it allows 'outside air' to freely enter the cab - how can we stop that flow?

That sounds confusing ;D.

How can I put it.............is there a scenario whereby the system is off and there is no air entering the cab?

The current design makes off mean off, as in absolutely no air flow what so ever. I think this is a bad idea for what will be an extremely well sealed cab.
BTUK think this too, this is why there has been a proposal to make off mean that a limited amount of non directed air from atmosphere gets circulated.

[prjb]

colin said:

I think you are reading more into my question than need be - all I'm asking is: can I have no air entering the cab if I choose?

Currently yea, but I think this isn't a good idea - hence the thread!

[prjb]

aspect said:

This all sounds a bit 1980's to me still !!! (sorry PRJB !)

Thats alright mate, this is the whole point of the thread!

aspect said:

My car has a climate control system - I set the temperature i want (the range is 16 degrees C to 29 degrees C ) (or continuous cooling or maximum heating) and the system maintains the environment at that temperature.
It defaults to conditioning the air, regardless of temperature (don't forget proper air conditioning DOESN'T have to cool the air), and drawing the air from outside.
However this can be over ridden by push buttons, to not condition and filter the air / to recirculate from inside / to adjust the fan speed. It also has options for briefly clearing windscreens etc.

Now that is a minimum of what i expect for a train cab in the 21st century ! No wonder ASLEF are going nuts about the diabolical state of train cabs.

The one switch offers you a temperature range whilst the other offers air flow speed. The system will attempt to maintain the selected temperature (which is similar to climate control). Currently you can have no air coming in but I think this is a bad idea. Also, you can't have a car type system on a train as a train is in use for a much greater period of time and a climate control system would be far too temperamental IMO. It needs to be simple and hard wearing.

aspect said:

A seperate "passive" heat supply is also a must in my view.
And a means of maintaining a rear cab at a proper useable temperature. (if you are on the Olympia shuttle, the trains cabs have no time to warm up before you change ends again)

Why is a seperate system a must? You want climate control quite strongly, yet you favour a secondary system which would counteract that? The unit has dual redundancy so shouldn't need secondary heater panels which will just interfere with the efficiency of the main unit.

aspect said:

As to the "fresh air" discussion, like Colin, I most certainly expect an option of no drawn air and neither heating nor cooling. I spend loads of time daily closing off all the vents on D stock to prevent air being drawn from outside ! (And every stock - bus and train - i've encounteed soon has plenty of drafts (draughts ?) to send a chill wind over you )

Stop thinking of current stock! These trains will not be draughty (_{he slips his head onto the block!} ;D ). I feel quite strongly that the cab should not have a position that stops all air flow. The proposed solution I am suggesting here would simply mean that in off a means of natural ventilation could occur. It wouldn't blow on you or really be noticeable, it just stops the cab getting dangerously stuffy.

[prjb]

donnytom said:

Surely the easiest thing for the drivers would be to make it like the controls in a car? Either the 'old' way of having a airflow rate controller and a temperature controller

That is basically what has been proposed, a switch for air speed and another for temperature.

donnytom said:

even a direction controller, or a newer "climate control" type.

There will be a car type vent at the driving position, and the proposed system is similar to climate control in that it will try to maintain the selected temperature.

donnytom said:

Then they can choose to have-

- air from outside the cab

That is currently the Emergency Vent option which I think should be moved to off (hence the thread).

donnytom said:

- air from an air-conditioning system

That is currently proposed.

donnytom said:

- recirculated air from the cab

No, the air will be 30% new and 70% recycled to keep it fresh. You can't keep recirculating old air.

donnytom said:

- no air

That is currently the off position, but I think this is a bad idea in a modern sealed cab.

donnytom said:

For that matter, would it be very difficult to fit a car system to the cab of a train, as they use roughly similar volumes of air and are reasonably compact?

We are bound not only by LU standards but also by Rail Group Standards and they both demand a huge amount of air. A car system would not meet the standards.

[donnytom]

Ah, I see. Thanks for demistifying this! (Speaking of which, will the windscreen have a demister or anything like that? ;D)

[Deleted]

prjb said:

Why is a seperate system a must? You want climate control quite strongly, yet you favour a secondary system which would counteract that? The unit has dual redundancy so shouldn't need secondary heater panels which will just interfere with the efficiency of the main unit.

Thanks for the detailed comments PRJB.

I take your point on the second system counteracting the first ;D

Perhaps I should rephrase that I'd like to see a back up system or at least somthing that will heat a cab before I get in it. It seems wasteful to run the "climate control of sorts" in the rear cab, but if it works thats fine. Again my cited example is the Olympia shuttle, where the cab doesn't have time to get warm (and that is with a passive heater going !) before you change cabs again.

On current stock we would have the passive heater running in both cabs all the time