Steam loco cylinders - more is better

[david.hill64]

54 minutes ago, MarkC said:

That or they attempted to seal the crack by brazing...

 

...the thought of either of those possibilities scares the **** out of me...

 

Mark

With the suggestion that either they didn't know what they were doing, which is scary, or they did, which is worse.

[The Stationmaster]

14 hours ago, The Johnster said:

 

Mr Lloyd, the WR Guard's Inspector who passed me out on Rules & Regs, stated he was happy with my performance and to let me loose on the railway, but to 'always remember, lad, that every one of these rules was found lying at the bottom of a bucket of blood', which in the early days it was.  And I always did remember.

The problem was that many did not, and alas even today some do not, remember that. What namatters is that safety related procedures should be built on commonsense and kept simple and to the point even when science and techinical inflomation his informed the writing of a procedure.

 

It seem to me that those who got it so worng on the SS Norway either didn't know or didn't follow procedures because they didn't fully or properly understand the reasons for them and in some cases the procedures were regarded as impractical.  Maybe the procedures were right (although not entirely as was the case in some respects there) or they were badly communicated without training and explanation of why they existed.   Anyone who deals with any steam pressure vessel, including railway engine boilers, surely ought to understand and fairly quickly learn, that it should only be brought from cold to working pressure at a pace which allows for gradual expansion and that letting it cool too fast can do even more damage.

[The Johnster]

I think it was a startling phrase to use, and if had the desired salutory effect on me; I've certainly never forgotten it.  I always regarded the rules and regs as a frontier beyond which lay dangerous chaos, which some thought a tad anal of me, but familiarity bred contempt and some of the old hands exhibited some daft habits which they had gotten away with for years, set in their ways.  Better to learn and stick to good habits, that way you won't be run down at night on the unofficial walking route...

 

Safety is a set of rules and methods, and equipment to use, but must be backed up by attitude.  People who look both ways before they cross the road even when they cannot hear any traffic know what I mean; constant affirmation of the habit of looking both ways means it becomes a Pavlovian default and you don't even have to think about it. 

[Siberian Snooper]

Warming and cooling, SHOULD be done slowly, especially the warming, boilers that have low thermal cycling tend to have less defects on inspection than those that don't.

 

Something that makes me cringe when I visit preserved railways, is when there's prolonged lifting of the safeties, or repeated lifting of the safeties. As far  as I'm concerned the crew should lift them briefly on leaving the shed and only further lifts, should there be a change of crew, there will be plenty of steam 5 or 10 pounds below the point of the need to lift the safeties. It's undue stressing oc the boiler, I know that it can't be helped on some occasions. It's also a waste of coal and water.

 

Glad I have got that off my chest.

 

 

[The Johnster]

Safety valves lifting is, I agree, a waste of steam, which means a waste of coal, water, and fireman's effort; a perfect fireman on a perfect engine with a perfect driver on a perfect road running as booked in a perfect world would have the valves 'feathering' when the maximum effort was needed and no more than the required pressure at other times.  But I'm not sure that I agree that consistant or constant valve lifting is unduly stressing the boiler, my reasoning being that it is the rapid changing of pressure that causes most of the stress (this, as well as the expansion of different metals and thicknesses of metals, is why it necessary to warm locomotives from cold slowly).  A boiler blowing off consistently is wasting steam sho' nuff, but the pressure is constant at the valve setting, and well within the boiler's design paremeters.

 

My specification for a modern steam locomotive would include feedback-controlled electronic boiler management connected to GPS, so that the boiler could be readied autonomously for expected accelleration or climbing banks, and allowed to ease off at the right time to avoid valves lifting.  A boiler management system would be needed anyway, as one of my other requirements is single manning for Driver-only operation.  Layshafts to avoid hammer-blow, cab-forward, recycled steam, chime whistle because I like them, and other ideas as well; pure fantasy of course.

[david.hill64]

1 hour ago, The Johnster said:

My specification for a modern steam locomotive would include feedback-controlled electronic boiler management connected to GPS, so that the boiler could be readied autonomously for expected accelleration or climbing banks, and allowed to ease off at the right time to avoid valves lifting.  A boiler management system would be needed anyway, as one of my other requirements is single manning for Driver-only operation.  Layshafts to avoid hammer-blow, cab-forward, recycled steam, chime whistle because I like them, and other ideas as well; pure fantasy of course.

With the exception of the GPS and cab forward, what you describe is a Shay on the Taiwan Alishan Forest Railway!

 

 

Edited August 9, 2023 by david.hill64

[The Stationmaster]

8 hours ago, david.hill64 said:

With the exception of the GPS and cab forward, what you describe is a Shay on the Taiwan Alishan Forest Railway!

 

 

As does this in some respects - built by SLM in 1996 for the BRB.  My photo taken during my 'Grand Tour' in 2003

 

[Michael Hodgson]

10 hours ago, The Johnster said:

 

My specification for a modern steam locomotive would include feedback-controlled electronic boiler management connected to GPS, so that the boiler could be readied autonomously for expected accelleration or climbing banks, and allowed to ease off at the right time to avoid valves lifting.  A boiler management system would be needed anyway, as one of my other requirements is single manning for Driver-only operation.  Layshafts to avoid hammer-blow, cab-forward, recycled steam, chime whistle because I like them, and other ideas as well; pure fantasy of course.

and as it needs to be carbon neutral, it will have a big immersion heater in the boiler, a pantograph fitted on the tender, regenerative braking, condensing apparatus to save water, no need for a mucky smoke box or ashpan, and no fire-irons.  No need for fire-wardens to chase the train down the line extinguising conflagrations started by hot cinders.  The driver will wear a white uniform 😁

[rodent279]

Going back to the original title of the thread, "Steam loco cylinders - more is better", in one sense Churchward agreed. The 2 cylinder Saints and 4 cylinder Stars (as originally built with 14.25" cylinders) are within 1% of each other in cylinder swept volume, and have virtually the same T.E., 24,395lbf & 25,090lbf respectively.

GJC's motivation for the greater complication & expense of 4 vs 2 cylinders was the smoother running at high speed brought about by the better balancing, which was better for the track, and lead to less wear & tear on the frames & axleboxes. It was supposed to lead drivers to operate on a shorter cut-off also, as longer cut-offs tend to cushion the pistons at the beginning & end of each stroke, thus resulting in greater fuel efficiency.

I wonder if there is also something inherently more efficient in expanding steam in 4 smaller cylinders, rather than expanding the same amount of steam in 2 larger cylinders?

[jjb1970]

On boilers, they're designed for the application, some boilers can be brought up to temperature and pressure very quickly and are designed for that (the whole point of remaining coal power plants is flexible operation, and WHRBs in CCGT plants have to follow the GT ramp up. Automatic boiler control, including power management which integrates turbines and boilers to control thermal gradients, load change etc have been normal for many decades, predating PLC technology. Nowadays it may be derided as stoneage technology but pneumatic PID controllers were very capable.

[MarkC]

2 hours ago, jjb1970 said:

Nowadays it may be derided as stoneage technology but pneumatic PID controllers were very capable.

Oh yes - the joys of being initiated into the Dark Arts of the Bailey Board...

 

Mark

[The Johnster]

16 hours ago, david.hill64 said:

With the exception of the GPS and cab forward, what you describe is a Shay on the Taiwan Alishan Forest Railway!

 

 

I envisage  the Grimsel (explanation later) as a Garratt(ish)with cabs each end and the engine centrally beneath the boiler driving a layshaft, coupled by CV joints to further layshafts beneath the bogies, Bullied-type casings to enable cleaning by carriage washers and for smokelifting, fired by oil or gas with possible electric element, or a combination is this is desirable.  It will also be capable of being moved at low speed and carry out local light engine and  light shunting duties on compressed air or other suitable gas.  
 

Driving bogies easily removable and come in three versions, a mogul with 5’ driving wheels capable of 90mph with 1,000 tons, and an 0-8-0 with 4’ drivers capable of 1,500 tons at 60mph, and a 4-4-0 with 7 ’drivers capable of 120mph plus with 400 tons.  There would be no reason not to mix bogies if this was thought to be advantageous, and the bogie layshafts will be able to be isolated in motion from the loco dection layshaft, so that that for example a 300ton train could be hauled at 120mph by the 4-4-0 end from Euston to Carnforth or Paddington to Newton Abbott, then the layshaft could be engaged on the Mogul or 0-8-0 bogie for the banks. 

 

The purpose would be Thunderbird and off-OHLE/3rd rail diversion work.  In service, say a diverted WCML service over the S&C, it would probably need at least one and possibly two 100-ton converted TEAs to carry water for non-stop services; oil or gas could probably be stowed on the engine.  I reckon a single TEA would give a ‘range’ of about 100 miles, enough for most work as while no -stop distances greater than this exist, they do not represent the bulk of main line work in the UK.  The TEAs would need to be baffled for FSA control, and could be replaced with full ones at station stops, using automatic couplings. There would be about 30 engine units and 60 of each type of bogie unit, with removable plug-in cabs.  Light steam between duties could be maintained at depots by grid electricity on 400v cooker circuits, probably several of them.  
 

I doubt they would ever be profitable, but as long as it was not stupidly costly this would not matter, as the point is to maintain the continuity of the service when there is no OHLE without removing motive power assets from paying work; the whole concept is of spare reserve capacity, anathema to current pare-it-back-to-the-bone TOC thinking.  No doubt they could recover some outlay on railtour duty, and would be cheaper to build and maintain than diesels built new for this dedicated purpose.  
 

The key to their success will be the effectiveness of the electronic feedback/GPS based boiler management system, which has to leave the driver completely free to observe signals and have the right amount of power available to him/her at all times as well as a safe level of water in the boiler without his/her having to concern his/herself; this is a major concern of the driver of a traditional steam engine and of course the overwhelming priority of his fireman, and the distraction caused has led to SPADs.  The Garratt-Richards Multipurpose Modular Steam Locomotive (GRMMSL, generally known as ‘Grimsels’; attached to down trains at Crewe they would be ‘grimsels oop north’) will have no instrumentation in the cabs concerned with the boiler, rate of steamraising, consumption of fuel and water, or anything else that might distract the driver from his primary function (that of stopping the train at the locations and time shown in the WTT while observing signals, correct dpeeds, snd Rules/Regs.  Boilers will be monitored and operated from a central control room which will be capable of full remote manual operation if needed.  
 

If you wanted, for railtour purposes, a boiler operator could ride in the train or on the loco, operating the boiler with a smartphone, with the information available online in realtime, but NOT where the driver can see it!

 

Like I said, pure fantasy, as much to do with reality as aMel Gibson historical epic…

[jjb1970]

Controlling boilers from a control room would be pointless given that things like automated water level and pressure control for boilers were well established  many decades ago. Marine propulsion boilers could operate as part of unattended machinery spaces with engines on bridge control pretty much at the time I was born. In terms of control engineering it's probably as simple as it gets, even accounting for level swell and shrink as the steam flow goes up and down. Not just PLCs, but you could do it with pneumatic controls very easily. With liquid or gas fuel boiler furnace conditions can be controlled to a very fine degree for clean combustion and low emissions and high efficiency (contrary to misconception, boilers can be extremely efficient in terms of energy in/out ratio, it is overall steam plant efficiency which isn't great). And if you did want to control them from a control room for some reason you'd need secure datalinks and telemetry with no dead spots, secure from interference etc (and if you do that, why even have a driver?). Modern boiler control interfaces are no more complicated or distracting than control interfaces for diesel engines.

 

I must admit I've always wanted to see something like the 5AT built. It'd be an exercise in futility in confirming that efficiency and performance of a reciprocating steam engine made with best available technology is hopeless compared to diesel and electric traction, but it'd be interesting. I just can't get enthusiastic about replica locomotives. If people like them then great (like what you enjoy and enjoy what you like) but to me they're just facsimile copies and don't have any of the heritage or sense of history that makes preserved trains interesting (I'm aware of the trigger's broom stuff and that it is highly questionable how much heritage they really represent, but still). And if you went for a Rankine cycle steam turbine or turbo-electric arrangement it moves away from the idea of seeing just what you could do with the Stephenson locomotive of you really tried and seems even more pointless.

[jjb1970]

21 hours ago, MarkC said:

Oh yes - the joys of being initiated into the Dark Arts of the Bailey Board...

 

Mark

 

Antiquated, primitive and the sort of gear you hoped wouldn't stop working but which was remarkably good given how primitive it was. The steam turbine box boat I was on ran like a sewing machine with very little intervention needed even though it relied on ancient 1960's era Bailey gear. When I went into electricity generation the boiler and steam turbine controls were all PLC and software based platform management systems and they really didn't do that much more than the old Bailey gear did when it came to the boilers.

[rodent279]

PLC in this context being Programmable Logic Controller?

[jjb1970]

Yes, sorry, should have spelt it out.

[johnofwessex]

I was in the boiler room of a steamship one day that shall remain nameless.

 

After chatting with the stoker he said to me 'you know a bit about this don't you, can you man th efort while I go for a quick break'

 

The joys of being in charge in a machinery space again!

[MarkC]

2 hours ago, jjb1970 said:

 

Antiquated, primitive and the sort of gear you hoped wouldn't stop working but which was remarkably good given how primitive it was. The steam turbine box boat I was on ran like a sewing machine with very little intervention needed even though it relied on ancient 1960's era Bailey gear. When I went into electricity generation the boiler and steam turbine controls were all PLC and software based platform management systems and they really didn't do that much more than the old Bailey gear did when it came to the boilers.

Always prefer pneumatic gear - as long as you've got good, dry air for it.

 

Oh, and don't let the damn Mate bxggxr about with the cargo plant controls either... "I was just fine tuning it, but now it's not working". The whole plant - banjaxed...  I asked said idiot to show me what he'd used - he produced a personal tool kit. He made the mistake of handing it to me. Oops - it accidentally fell over the wall...

 

Mark

[The Johnster]

9 hours ago, jjb1970 said:

Controlling boilers from a control room would be pointless given that things like automated water level and pressure control for boilers were well established  many decades ago. Marine propulsion boilers could operate as part of unattended machinery spaces with engines on bridge control pretty much at the time I was born

 

(Vicky Pollard voice) Yeah but no but yeah but no but yeah but...

 

More control input would be needed on a railway locomotive than would normally be encountered in a marine or industrial application as the ideal amount of steam required depends on several interacting factors.  The loco has to speed up and slow down, obey speed limits, respond to signals, climb hills, and roll down the other side; demand for steam is only fairly predictable in normal circumstances so long as you know the loco's location and the load, but at 90mph you are covering a mile every 45 seconds, so the Grimsel's management electronics have to predict demand and still be able to be configured to deal as effectively as possible with anything unforeseen such as Stephenson's coo.  And the principle is that the driver is there to drive and only to drive, and not concern himself with the steamraising.  A central manned 'control room' will be needed as backup, and could probably handle several boilers simultaneously from a smartphone,

[jjb1970]

The key parameters of boiler performance are evaporation rate, steam temperature (degrees of superheat) and pressure. What the steam is used for is pretty much irrelevant to a boiler control system, it is only concerned with maintaining pressure, evaporation and water level. That's a very simple issue for a boiler control system. Whether those changes are because a train is going uphill, slowing down for a signal, obeying a speed limit or anything else is no different from any other transient condition. Why would you need a central manned control room to implement a control function that was routine 70 or 80 years ago with technology which would be considered painfully primitive today?

Edited August 11, 2023 by jjb1970

[johnofwessex]

It was interesting to hear Captain John Megoran, Master of Kingswear Castle talking about operating the ship, the particular joy they had to deal with was the Kingsferry Bridge, you could be steaming towards the bridge against the tide so with a boiler full of coal then have to wait for it to open 

[Jeremy Cumberland]

8 hours ago, The Johnster said:

...and still be able to be configured to deal as effectively as possible with anything unforeseen such as Stephenson's coo. 

Okay. I give up. Stephenson's what?

[LMS2968]

It was George Stephenson's reply to a question about a train should it hit a cow on the line. In his broad Geordie accent he replied, "It would be very unfortunate - for the coo."

[rodent279]

6 hours ago, jjb1970 said:

The key parameters of boiler performance are evaporation rate, steam temperature (degrees of superheat) and pressure. What the steam is used for is pretty much irrelevant to a boiler control system, it is only concerned with maintaining pressure, evaporation and water level. That's a very simple issue for a boiler control system. Whether those changes are because a train is going uphill, slowing down for a signal, obeying a speed limit or anything else is no different from any other transient condition. Why would you need a central manned control room to implement a control function that was routine 70 or 80 years ago with technology which would be considered painfully primitive today?

Would oil firing be necessary with modern control systems? Could pulverised coal be used?

And would the control eystem need to know about the calorific value of the coal?

[jjb1970]

53 minutes ago, rodent279 said:

Would oil firing be necessary with modern control systems? Could pulverised coal be used?

And would the control eystem need to know about the calorific value of the coal?

 

You could use pulverised coal, but these days if oil is politically difficult then coal is positively toxic. Materials handling would be difficult (but no doubt doable) too. Pulverising plant onboard, or perhaps fluidised handling of pre pulverised coal. That requires very careful risk management.

 

On calorific value, the combustion system would be optimised around that but once the combustion system is optimised and things like fuel air curves wired into the combustion management part of the boiler control system then it is generally more steam = more fuel and less steam = less fuel.