Keep Down Smoke

Inside the fence.
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jim s-w
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Keep Down Smoke

Postby jim s-w » Mon Apr 18, 2016 5:12 pm

I found the above notice in a 1939 picture of Kentish Town shed.

What does it mean and how was it done?

Jim

garethashenden
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Re: Keep Down Smoke

Postby garethashenden » Mon Apr 18, 2016 6:14 pm

I believe that the driver has some control over the amount of smoke produced. It is something to do with the regulator position and the cutoff setting.

I do know of a photographer in America who would put out signs by the track saying "Photographer ahead! Make Smoke!". The train crews would usually oblige.

John Palmer
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Re: Keep Down Smoke

Postby John Palmer » Mon Apr 18, 2016 6:25 pm

I assume it's an admonition to preparation crews, in particular, not to put too much coal on newly laid fires. Doing so leads to a poor fuel/air mix and the liberation, unburned, of the volatile constituents of the coal in the form of large quantities of smoke, which does not go down well with the neighbours occupying nearby residential property.

mickeym
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Re: Keep Down Smoke

Postby mickeym » Mon Apr 18, 2016 10:06 pm

As above
any fire when newly lit tends to create a lot of smoke, if it is "over done" with fuel, compared to one that is slowly brought to life with care - My neighbours know I know this well :D

Julian Roberts
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Re: Keep Down Smoke

Postby Julian Roberts » Tue Apr 19, 2016 6:30 am

Jim

From 2012-14 I was a fireman on the Welsh Highland Railway, and hope to resume there sometime, and have been on the Bala Lake Railway since 1999 though more recently was promoted to glory... Being a fireman is a constant juggling act of balancing the amount of fire and the amount of water in the boiler. Having to worry about the smoke is a bit like having one of your hands tied behind your back while juggling two balls at once.

Where there is proximity to housing it is a big problem of good neighbourliness to keep down the smoke, and it is the mostly up to the fireman. It is never far from our minds that the railway is not welcomed by some locals. Additionally in the Snowdonia National Park pollution of any kind is unwelcome, and smoke is a very obvious form of it.

The WHR has two sheds, one at Dinas (near Caernarfon) and one shared with the Festiniog Railway at Boston Lodge near Porthmadog. At the latter there are no houses nearby but at Dinas there are.

The amount of smoke created in the first place varies according to the smokiness of the coal. On both railways we use Russian or Welsh coal according to the current price or value. Welsh coal is far less smoky.

In the second place the smokiness depends on the amount of suck or airflow through the fire. When the loco is working the exhaust steam rushing up from the cylinders through the chimney draws the fire. When the driver shuts off steam, there can be a sudden increase in the smokiness of the exhaust if there is still unburnt coal in the fire. The blower is one of the fireman's main tools, and creates this suck artificially, using steam to draw the fire, and (s)he should open it in this situation (yes, there are lady firemen!... not referred to as firepersons...)

When steam is being raised on the WHR we have a compressor to create this draw until there is enough steam pressure for the blower to work.

In the third place, yes, putting on a little at a time helps, though when lighting up we want the fire to be covering the whole grate as soon as possible to raise steam, and that is when the most smoke is created. The slower you do it the earlier you needed to have been there, and a 10am train departure from Caernarfon means being there around 6 as it is...!

In the fourth place the smokiness depends on allowing "secondary air" (or "top air") into the firebox, on the WHR Garatts this is by leaving the firedoors open a crack. The smokiness of the coal is at its maximum just after you put it on, and fairly soon each shovelful's smoke is burnt off, while there is plenty more heat to be got out of that coal.

In the fifth place, the smokiness varies surprisingly according to where you put it on the grate. At the back, just under the firedoor, a shovelful creates a lot less immediate smoke than at the front.

The BLR with its little Alice Class Quarry Hunslets has far less of a problem, and its shed at the other end of the line, Llanuwchllyn, is not immediately by the village. But all the same principles apply.

To illustrate some of the juggling:

Opening the blower will make the fire work harder, raising steam more quickly. Opening the firebox doors can cool the tubeplate and cause damage. When we are waiting to leave from Porthmadog the second worst sin is smoke, with a lot of residents around, some of whom are not very friendly to the railways. But the first sin is blowing off, because of the noise it creates, as well as being a very obvious indication that too much coal has been used and is having to be wasted with this lost steam. Just one lifting off of the safety valves is "allowed" each day, any more is an indication of poor firing...!

As we leave Porthmadog enough steam to move the train is all that is essential, and the fire can be built up as soon as we are leaving the town, and there is about 15 minutes of hard work "on the flat" (over the "Traeth", the beautiful flat and rich agricultural land created by the building of the Cob for the Festiniog Railway) to get the boiler full and get pressure to maximum before we hit the "ski jump", Nantmor Bank, where the 1 in 40 abruptly starts and that is almost continuous up to the Rhyd Ddu line summit.

At Caernarfon we sometimes have a long wait at lunchtime, so want to arrive with a spent fire and plenty of room in the boiler. so that keeping the fire alive doesn't create too much steam. There are lots of houses immediately above by the line here though hidden behind the high wall, on the landward side. Prior to leaving the pressure has to be raised and boiler filled without creating too much smoke for the hard slog to Dinas and then the first summit at Tryfan Junction.

The Russian coal is easier to use, it ignites quickly and has a much more immediate effect, but is spent more quickly. The Welsh coal delivers more heat, and works at a higher temperature, so you use less of it, but is slow to ignite, so can be more difficult lighting up, and it can create clinker more easily.

Mostly entirely irrelevant in 4mm scale...!

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Will L
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Re: Keep Down Smoke

Postby Will L » Tue Apr 19, 2016 7:51 am

Julian Roberts wrote:J...Mostly entirely irrelevant in 4mm scale...!


But fascinating anyway. Thank you.

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chrisf
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Re: Keep Down Smoke

Postby chrisf » Tue Apr 19, 2016 8:58 am

"From 2012-14 I was a fireman on the Welsh Highland Railway, and hope to resume there sometime, and have been on the Bala Lake Railway since 1999 though more recently was promoted to glory..."

I feel bound to point out that in Salvation Army speak "promoted to glory" is a nice way of referring to death!

Chris

Julian Roberts
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Re: Keep Down Smoke

Postby Julian Roberts » Tue Apr 19, 2016 12:40 pm

Exactly Chris. I am in heaven when I'm driving the BLR train. You should come sometime if you don't know the line. It's beautiful.
In fact if I'm with another driver we swop half way through the day. Firing is equally fun.

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jim s-w
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Re: Keep Down Smoke

Postby jim s-w » Wed Apr 20, 2016 8:23 pm

Thanks all

I really had no idea the crew could control this sort of thing.

Jim

dal-t
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Re: Keep Down Smoke

Postby dal-t » Thu Apr 21, 2016 8:53 am

Perhaps worth remembering that legal approval for many early railways depended on locomotive engines 'consuming their own smoke'. Not so difficult (in terms of the desired effect - let's not get into the physics of it) when the fuel was coke, but after the discovery of the brick arch and the switch to coal, a condition more honoured by the breach than the observance. There remained, however, a level of expectation reflected in the sort of notice under discussion.
David L-T

mickeym
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Re: Keep Down Smoke

Postby mickeym » Fri Apr 22, 2016 9:16 pm

Buy a wood burning stove and see it all in reality - its just the same; but it doesn't move.
In large engine sheds, one sees "canopies" where the locomotive engines were fired up - They are not to take the smoke away, smoke obviously rises anyway - They act like an extension to the chimney to get that all important draft pulling properly.

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steve howe
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Re: Keep Down Smoke

Postby steve howe » Thu May 19, 2016 11:01 am

mickeym wrote:Buy a wood burning stove and see it all in reality - its just the same; but it doesn't move.


We have a wodburner and a multi fuel stove and I am regularly "told off" for fiddling with the controls, but it does illustrate the point. My neighbours have an old solid fuel Aga which demands real skill in driving... Must be the domestic equivalent of having a 'duchess' in the kitchen!

Steve


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