The sound of Southern Locos compared to LM/BR Locos

[The Johnster]

Curses, Batman, confounded by erudition and thermal inefficiency! 

 

It has long been my view that the thermal efficiency of lack of it of steam locomotives is not important in terms of operating the locos in traffic, so long as the work required of the loco's engine can be supplied with sufficient steam, which means that the boiler can convert enough water into steam to equal or, better, exceed the rate at which the steam is being used.  If the loco were driven at speed at the same regulator and gear settings as are used to slog up banks or get away from stations, the boiler would be empty of steam within half a mile and the fire would have to be dropped.  The cylinders are using much less steam per piston stroke 'cruising' at 90mph on the level but they are using this lesser amount more quickly, are they not?  The loco is not being driven 'flat out' and only needs enough steam to the cylinders to keep momentum and haul the train.

 

It is of no matter so long as the driver doesn't waste steam, and the fireman can keep up with the firebox's demands as well as his other duties.  One can even increase the power for short periods if an easy stretch is on the horizon and the fireman can restore pressure once the throttle, and gear, are eased; I believe this is what is known as 'mortgaging the boiler'.  It is an advantage over diesel traction which, once full power is applied, has nothing in reserve and if the train is failing to keep time nothing can be done about it.

 

Engineers eventually designed a highly thermally efficient means of powering a locomotive; it's called a Nuclear Power Station, National Grid, and OLE.

 

This is a gross oversimplification as any understanding of mine of the engineering and driver/fireman's methods of handling locos must be.  It was once explained to me by an old Canton driver that the revolution of the driving wheels drives the pistons in the cylinders which in turn create a draw on the fire to maintain steam in the boiler so he can have a cup of tea at 90mph with 14 on, and the fireman's job was to make sure there was steam at the pep pipe for this purpose.  On a diesel, the driving wheels revolve to produce electricity or hydraulic pressure with somehow, he didn't fully explain this, enabled the engine to produce power to run the hotplate so he could still have his cup of tea at 90mph, but with only 10 on, such was progress...

 

I love this sort of pointless nonsense; not only did it pass away the long night shift hours amiably and harmlessly enough, it makes you think about how things work from a different perspective.  When I tried unsuccessfully to learn Welsh some years ago I was delighted to find that toes, in Welsh, are bys droed, literally foot fingers, which is exactly what they are but I'd never thought of them in this way.

[Philou]

I'll see your bys droed and raise you a popty ping - not quite TTS sound - sorry OP.

 

Cheers,

 

Philip

 

Whilst I think of it, @The Johnster isn't the description the other way round regarding the wheels and pistons? The pistons push the wheels via the conrods and cranks? Or have I that wrong under particular circumstances?

[Nearholmer]

Best way to get a good gut feel for the physics of motion is to buy a bike, and ride it a fair bit.

 

You instantly get to appreciate that, starting with a level road and no wind blowing, some effort is needed to accelerate a mass (self and bike: loco and train) up to a given speed, but that once said speed is attained, relatively less effort is needed to maintain it, and that the effort needed to overcome air resistance increases very markedly with speed (especially, if like me, you aren't particularly streamlined!).

 

Start adding in gradients, up and down, then wind, add mass by loading your panniers to maximum etc, and you can literally feel the physics.

 

Efficiency-wise, a person on a bike is probably about twice as energy efficient as a steam loco (food/fuel energy converted to work), somewhere around 20% for a person, 10% for a steam loco.

 

 

[The Johnster]

13 minutes ago, Philou said:

I'll see your bys droed and raise you a popty ping - not quite TTS sound - sorry OP.

 

Cheers,

 

Philip

 

Whilst I think of it, @The Johnster isn't the description the other way round regarding the wheels and pistons? The pistons push the wheels via the conrods and cranks? Or have I that wrong under particular circumstances?

You are right and the old driver was being very silly.  

[The Johnster]

25 minutes ago, Nearholmer said:

Best way to get a good gut feel for the physics of motion is to buy a bike, and ride it a fair bit.

 

You instantly get to appreciate that, starting with a level road and no wind blowing, some effort is needed to accelerate a mass (self and bike: loco and train) up to a given speed, but that once said speed is attained, relatively less effort is needed to maintain it, and that the effort needed to overcome air resistance increases very markedly with speed (especially, if like me, you aren't particularly streamlined!).

 

Start adding in gradients, up and down, then wind, add mass by loading your panniers to maximum etc, and you can literally feel the physics.

 

Efficiency-wise, a person on a bike is probably about twice as energy efficient as a steam loco (food/fuel energy converted to work), somewhere around 20% for a person, 10% for a steam loco.

 

 

I believe M. Chapelon got it up to 18%.  I doubt if I ever rode a bike at 20% efficiency; my arms are too short in proportion to the rest of me, compounded by small hands.  The thing about small hands isn't true btw.  I have never been able to touch my toes, which was the cause of a huge amount of unnecessary suffering in school gymnasiums from P.E. ubergruppensturmfuhren who thought I was lying and attempted to crack my spine in an attempt to prove it.  At full stretch of my arms and fingers, back straight now, boy, I was about 3 inches short.  No bicycle frame designer has ever understood this, nor that even before I put the weight on setting the saddle to the correct height still meant that with every upstroke my thighs squashed my stomach and forced it up into my chest, so I could never really breath properly.  Drop bars are a major no-no for me.

Edited August 12, 2020 by The Johnster

[62613]

1 hour ago, Nearholmer said:

Best way to get a good gut feel for the physics of motion is to buy a bike, and ride it a fair bit.

 

You instantly get to appreciate that, starting with a level road and no wind blowing, some effort is needed to accelerate a mass (self and bike: loco and train) up to a given speed, but that once said speed is attained, relatively less effort is needed to maintain it, and that the effort needed to overcome air resistance increases very markedly with speed (especially, if like me, you aren't particularly streamlined!).

 

Start adding in gradients, up and down, then wind, add mass by loading your panniers to maximum etc, and you can literally feel the physics.

 

Efficiency-wise, a person on a bike is probably about twice as energy efficient as a steam loco (food/fuel energy converted to work), somewhere around 20% for a person, 10% for a steam loco.

 

 

 

10% efficiency is a bit optimistic for a simple expansion steam loco, isn't it? I've seen figures which suggest 5% - 7% max. Dr. Porta reckoned he could up it to 12% with his modifications, I think.

 

[Nearholmer]

I was being kind to steam locos, yes. 6% is usually cited as a ready-reckoner.

 

I've never seen 18% cited in connection with Chapelon, usually something like 12 or 13%, similar to Porta, which sort of doesn't make sense, so I need to go and look in very dense books.

[62613]

43 minutes ago, Nearholmer said:

I was being kind to steam locos, yes. 6% is usually cited as a ready-reckoner.

 

I've never seen 18% cited in connection with Chapelon, usually something like 12 or 13%, similar to Porta, which sort of doesn't make sense, so I need to go and look in very dense books.

Remember that most engines lost a fair amount of unburnt fuel straight up the chimney, due to the blast, especially when working hard. Porta's Gas Producer combustion system was supposed to cut this down, which increases efficiency, surely, just by burning more of the fuel. Then there were the heavily lagged cylinders, and so on.

[Tallpaul69]

An amusing line of discussion folks!

 

Meanwhile following my investigations of SR locos v LM/BR locos, I found some useful information on South West Digital's web site, although this mainly suggests which locos in each of the four Grouping companies and BR loco fleets can be replicated by the same sound files.

So for instance, it backs up my decision to use the newly introduced Hornby TTS Hall decoder in Counties, Granges and  28xx class locos!

Once I have got by head round the relevant SR/LMR/BR data, I will post a distillation of it here.

 

Aagh!!

It has just started tipping it down here in south Bedfordshire for the second time today, so it looks like I shall not be venturing down the garden to my Model Room again today.

Best regards

Paul  

[SRman]

7 hours ago, Tallpaul69 said:

An amusing line of discussion folks!

 

Meanwhile following my investigations of SR locos v LM/BR locos, I found some useful information on South West Digital's web site, although this mainly suggests which locos in each of the four Grouping companies and BR loco fleets can be replicated by the same sound files.

So for instance, it backs up my decision to use the newly introduced Hornby TTS Hall decoder in Counties, Granges and  28xx class locos!

Once I have got by head round the relevant SR/LMR/BR data, I will post a distillation of it here.

 

Aagh!!

It has just started tipping it down here in south Bedfordshire for the second time today, so it looks like I shall not be venturing down the garden to my Model Room again today.

Best regards

Paul  

You may also find similar suggestions for 'shared' sounds on the YouChoos website.

I wanted sound for a Hornby 700 class 0-6-0, and the suggestions for that were eitehr the Drummond M7 or the Drummond T9. I chose the T9 sounds, and with advice from John (of YouChoos), adjusted the chuff rate to match the wheel revolutions of the 700 while running it on the rolling road.