Bulleid's Leader: could it have even been successful?

[rodent279]

On being OT: the originator of this thread must despair. The basic answer ('no') seems to have been agreed pretty quickly, with little or no disagreement, after which we've all gone on to talk about a hundred, I admit in my case tenuously connected, other subjects!

 

K

 

Though, if I was the OP, I'd be quite pleased about what an interesting and wide-ranging discussion I'd created!

[Baby Deltic]

I think the leader would have been a success at killing firemen with heat exhaustion stuck between two boilers wearing leather chaps over their trousers to protect them from the heat. If you look at classes 59 and 66, the 'Leader look' with the shed roofed body with a high floor pitched on heavy steel framed bogies has made a comeback. Certainly the roof profile of nearly all the modern locomotives and wagons has the Bulleid's Leader profile. And of course we have Mr Bulleid to thank (and Mr Ivatt) for doing all the ground work to make class 40's and Peaks possible with Bulleid's bogies, and certainly in the case of the Peaks, Mr Ivatt 's look. Four classes of diesel loco that were an overall success.

Edited July 8, 2017 by Baby Deltic

[jjb1970]

Technology life cycle is a very interesting discussion, as are those rare transformational jumps. The introduction of railways transformed societies in ways which are hard to overstate, in many ways they became the glue that held countries together, provided unheard of social and industrial mobility and even facilitated standard time and common languages. The transition from sail to steam at sea was another transformational change of great profundity but it is also true that maritime international trading links have existed for millennia. Since then there have been other great changes, such as the transition from steam railways to diesel and electric, which have been of immense importance in terms of boosting performance and efficiency but which were far less profound than the initial introduction and are closer to the changes for shipping when sail gave way to steam. The Internet and networked systems was a really profound change in society (for those who doubt this, it is worth trying to have a few days with no connectivity and realising just how different life feels), and I believe the transition we are now in in terms of energy conversion (the post oil and fossil hydro-carbon economy) will be seen as another of these great jumps which will change how we live in ways which we can't really predict with any certainty.

The internal combustion engine was developed pretty far as much as it will be developed many years ago. Of course there have been improvements and it will continue to improve, but we long ago entered the marginal gains phase and designers are extending huge effort and investment to make improvements which whilst real are not dramatic. Materials science improvements and techniques such as FEA have allowed them to shed weight quite dramatically over the last 30 or 40 years, we now see very high charge air pressures which increases energy density greatly as well as efficiency, software based thermodynamic analytical tools has facilitated combustion improvements, and digital engine control has allowed a degree of engine control and configurability which would have seemed fantastical not that long ago but despite all this an engine is fundamentally still an engine. If I look at ships, yes a modern diesel is far superior to an equivalent engine of 30, 40, 50 years ago but it is also true that for the most part it doesn't do anything that engines of those older eras couldn't do in terms of powering a system, albeit they'd use more fuel and be bigger and heavier.

[cheesysmith]

I think the leader would have been a success at killing firemen with heat exhaustion stuck between two boilers wearing leather chaps over their trousers to protect them from the heat. If you look at classes 59 and 66, the 'Leader look' with the shed roofed body with a high floor pitched on heavy steel framed bogies has made a comeback. Certainly the roof profile of nearly all the modern locomotives and wagons has the Bulleid's Leader profile. And of course we have Mr Bulleid to thank (and Mr Ivatt) for doing all the ground work to make class 40's and Peaks possible with Bulleid's bogies, and certainly in the case of the Peaks, Mr Ivatt 's look. Four classes of diesel loco that were an overall success.

As for the look of trains being down to the leader, no, the look of trains is down to the loading gauge. We have the curved tops due to the fact that bridges were built with arches because the Romans proved the arch was a very strong shape for use with masonry and we didn't have the use of steel beams to make the holes the trains had to go through (bridges) square.

 

As for the bogies from the southern diesels being used under the peaks and the 40s, let's use a massively heavy plate frame bogie with poor suspension and a habit of cracks instead of trying to make the loco lighter. The peaks and the 40s had the same weight, even though the peaks in the twin bank sulzer engine had a engine that was 8 to 10 tonnes heavier.

 

If the warren trust girder body design of the peaks had been used with the EE engine, you could have built a version of the LMS twins (10000 & 10001) with a lower axle load and used the bogies already designed that went on for many years of excellent service under the EM2s. Using this you could have used EE bits in a loco of 120 tons with a HP of 2400 (EE did have a intercooled version of the Mk2 CSVT at the time the peaks were built) in a Co Co Vs the use of sulzer engines in a 1Co Co1 of 130+ tons with 2500 HP.

 

The only reason the bogies were used was to keep the axle load down, for use on the limited axle load lines, that most of such lines were closed down anyway. It was a answer that was there for a problem, with all of it faults, instead of trying to solve the problem of making the loco lighter.

 

As for the use of a heavy under frame to which everything else is attached. This is just because it is simpler and cheaper to do it this way. The later versions of the 66 come with smaller fuel tanks to keep within the weight limit because the environmental kit fitted weighs more. If they had been built like the 60s with a monocock body, well, look at the 67s, same mechanical bits and HP in a loco 40 tons less.

 

The problem of the leader Vs diesels/electrics is very simple. A electric motor is nearly perfect for use in land transport, as it has maximum toque at starting. Every thing else, steam, mechanical drive etc doesn't so you are introducing losses into the drive trains to compensate. If a steam loco makes most power at say 20mph, you have to make it more powerful to get the train moving at the start than you actually need.

[asmay2002]

I guess you could sum that up by saying there are limits as to how "good" any system/technology/machine etc can be. For example, despite having having had internal combustion engines for well over a century now, the thermal efficiency has remained almost unchanged in decades. Even the very best struggle to attain 50%.

Some vaguely remembered thermodyanmics tells me that the theoretical limit of cylinder efficiency is something like the temperture drop divided by the the higher (starting) tempetature (all expressed in Kelvins) so that 50% efficiency if nto above would be close to the abosolute limit anyway.

[LMS2968]

The problem of the leader Vs diesels/electrics is very simple. A electric motor is nearly perfect for use in land transport, as it has maximum toque at starting. Every thing else, steam, mechanical drive etc doesn't so you are introducing losses into the drive trains to compensate. If a steam loco makes most power at say 20mph, you have to make it more powerful to get the train moving at the start than you actually need.

No, a steam engine produces its maximum torque, and therefore tractive effort, at zero rpm, but it falls off exponentially as rpm rises. An internal combustion engine produces zero torque at zero rpm. The result is that both steam and electric do not need to be running at all times, but an ICE must have sufficient rpm to at least overcome its own internal resistances, and then a further rise in rpm is need to generate sufficient torque to overcome the inertia of the train being started.

[Nearholmer]

Yep.

 

The whole history of internal combustion locos is about transmissions much more than engines.

 

The very first attempts, c1880, are very interesting because some of the pioneers were clearly trying to use internal combustion engines as if they had the characteristics of steam engines or dc series motors.

 

K

[jjb1970]

Transmissions are often the bit that people ignore. Even if you only consider diesel-electric drive there are options, the most important of which are probably AC vs. DC. In marine applications now there is increasing interest in DC networks as it allows you to de-couple engine speed from network frequency and get rid of heavy circuit breakers (the "breakers" formpart of the solid state converter drives). I must admit, I've asked electrical colleagues why you couldn't have a variable speed generator with conversion equipment to a constant speed AC distribution system and never really got a satisfactory answer. These days the problems of AC harmonics and distortion from the use of converter drives seem pretty well understood and manageable.

[runs as required]

The whole history of internal combustion locos is about transmissions much more than engines.

The very first attempts, c1880, are very interesting because some of the pioneers were clearly trying to use internal combustion engines as if they had the characteristics of steam engines or dc series motors.

Is steam itself not a form of transmission?

I used to wonder about this when we spent happy afternoons driving engines in Kumasi Ghana when the kids were small.

The locos we drove were oil fired with a spray into the firebox  controlled by a valve.

 

If we approached a long load of timber waggons, up we turned the spray, black smoke belched out the chimney and after we'd coupled up, we'd haul the lever over into reverse and off we would go back to the station alongside the lorry park.

While we waited for the next movement, we'd watch the over-loaded tro-tros grind out onto the road, black smoke belching out of their Bedford/Perkins engines.

 

No difference really, but a great way of spending an afternoon.

 

dh

[Horsetan]

Though, if I was the OP, I'd be quite pleased about what an interesting and wide-ranging discussion I'd created!

 

Yes, it's like pulling the pin on a hand grenade, lobbing it in, then watching from a safe distance to see what happens.... 

[LMS2968]

Is steam itself not a form of transmission?

I used to wonder about this when we spent happy afternoons driving engines in Kumasi Ghana when the kids were small.

The locos we drove were oil fired with a spray into the firebox  controlled by a valve.

 

If we approached a long load of timber waggons, up we turned the spray, black smoke belched out the chimney and after we'd coupled up, we'd haul the lever over into reverse and off we would go back to the station alongside the lorry park.

While we waited for the next movement, we'd watch the over-loaded tro-tros grind out onto the road, black smoke belching out of their Bedford/Perkins engines.

 

No difference really, but a great way of spending an afternoon.

 

dh

The boiler is the source of power, which is transferred to the engine in the form of heat and pressure. The steam engine therefore uses power generated externally, i.e. in the boiler. Likewise, an electric motor uses external power, from a battery, power station or generator / alternator, which itself needs a power source. The diesel, and petrol, etc. engine produces the power within itself, hence the need for it to be running to produce any, and the term Internal Combustion Engine.

 

But steam is not the form of transmission, any more than is diesel fuel.

[rodent279]

Some vaguely remembered thermodyanmics tells me that the theoretical limit of cylinder efficiency is something like the temperture drop divided by the the higher (starting) tempetature (all expressed in Kelvins) so that 50% efficiency if nto above would be close to the abosolute limit anyway.

 

Yes, I vaguely remember something similar from engineering science lessons a couple of decades ago

The same law also limit the cylinder efficiency of a steam loco.

[rodent279]

The boiler is the source of power, which is transferred to the engine in the form of heat and pressure. The steam engine therefore uses power generated externally, i.e. in the boiler. Likewise, an electric motor uses external power, from a battery, power station or generator / alternator, which itself needs a power source. The diesel, and petrol, etc. engine produces the power within itself, hence the need for it to be running to produce any, and the term Internal Combustion Engine.

 

But steam is not the form of transmission, any more than is diesel fuel.

 

I don't know.......you could argue that power is generated in the firebox, transmitted to the boiler, stored in the steam, then the steam is used as a transmission fluid, in either a reciprocating engine (pistons in cylinders), or a rotary engine (turbine). You could use that steam to drive a turbine generating electricity, which then powers traction motors, as in the Ljungstrom loco and it's siblings, a concept used with some success in Sweden & the USA. You could even use the steam to drive a turbine pressurising oil, to drive a hydraulic final drive if you wanted. Odd, but it could be done.

 

Perhaps we ought to look upon the boiler/firebox of a steam loco as the "engine", in much the same way as the 12CVST EE power unit in a class 37 is the engine. That is where the power is generated. In a steam loco, the steam is the working fluid, and we use that to convert from heat energy to mechanical energy in either reciprocating cylinders, or a turbine.

 

This could run and run, there is no real clear dividing line. The term "mechanical/hydraulic/electric final drive" would perhaps be more appropriate.

Edited July 8, 2017 by rodent279

[jjb1970]

Steam is the working fluid in a heat engine, I wouldn't call it a transmission. And yes, the theoretical thermodynamic ideal of a heat engine remains the Carnot cycle in which thermal efficiency is a function of the ratio if Tmin to Tmax.

[jjb1970]

There was a thread in the wheeltappers section a while ago which turned into something of a discussion of theoretical heat engine cycles, it was about Rudolf Diesel. I suspect I may have appeared to be something of a puritan on the subject but the significance of these cycles is often poorly appreciated. Although they are ideals and not attained by real engines they still form ideals around which real engines are designed. The Carnot cycle is purely a theoretical ideal yet it remains the benchmark against which other cycles (eg. Diesel, Otto, Miller, Stirling, Atkinson) are judged.

[runs as required]

I don't know.......you could argue that power is generated in the firebox, tranmsitted to the boiler, stored in the steam, then the steam is used as a transmission fluid, in either a reciprocating engine (pistons in cylinders), or a rotary engine (turbine). You could use that steam to drive a turbine...which then powers traction motors, as in the Ljungstrom loco and it's siblings, a concept used with some success in Sweden & the USA. You could even use the steam to drive a turbine pressurising oil, to drive a hydraulic final drive if you wanted. Odd, but it could be done.

 

This could run and run, there is no real clear dividing line. The term "mechanic/hydraulic/electric final drive" would perhaps be more appropriate.

That's exactly what I used to perversely argue with a Mech Eng. course student I shared digs with back in student days - much to his annoyance when he was swotting up for his 'heat engines' exams.

(He got back at me on structures when I'd think of a section, then check whether it was adequate)

 

Going back to W Africa: I could not think of anything more decrepit than a foul old Bedford truck belching diesel and a barely alive 0-8-0T, still proclaiming its Gorton origins, trailing bunker oil? along weed infested tracks.

Amazing what can still be flogged into life in such places by resourceful 'wayside fitters' a long way away from OVSB !

dh

 

PS

I used to work in a Liverpool building with a hydraulic lift connected to a city centre mains network powered by a coal fired engine house down on the docks.

Edited July 8, 2017 by runs as required

[Edwin_m]

Transmissions are often the bit that people ignore. Even if you only consider diesel-electric drive there are options, the most important of which are probably AC vs. DC. In marine applications now there is increasing interest in DC networks as it allows you to de-couple engine speed from network frequency and get rid of heavy circuit breakers (the "breakers" formpart of the solid state converter drives). I must admit, I've asked electrical colleagues why you couldn't have a variable speed generator with conversion equipment to a constant speed AC distribution system and never really got a satisfactory answer. These days the problems of AC harmonics and distortion from the use of converter drives seem pretty well understood and manageable.

That sounds very much like the "DC link" in an electric train with AC motors.  A set of electronics converts the incoming AC to DC and another one uses that to generate AC at variable voltage and variable frequency to achieve desired motor speed and torque.  The whole lot can run in reverse to regenerate power, and harmonics were a big problem in the early years.  I imagine a diesel loco with AC drive is similar, but with no regeneration the first set of electronics is replaced by an alternator and rectifier. 

[rockershovel]

Surely the REAL point is that a steam engine is fundamentally different from an IC or electric one, in that it is not self-contained? It COULD be, in the sense of a "donkey" engine, but doesn't need to be. Nearholmer' point about early IC pioneers trying to use them as though they were analogous to steam engines, applies here - the Hildebrand and Wolfmuller motorcycle, for example. https://m.youtube.com/watch?v=jbbsDds1tbU

Edited July 9, 2017 by rockershovel

[rockershovel]

Following the "hand grenade" principle, although I'm inclined to think that it's more along the lines of "herding cats", here's a Hunslet 0-8-0T at Kumasi

 

http://steam-locomotives-south-africa.blogspot.co.uk/2008/07/

[rockershovel]

Re hydraulic power in Liverpool, Manchester and London also had such networks.

 

The London Hydraulic Power Company finally ceased transmission in 1977, and was bought by Mercury Communications. The LHP owned around 180 miles of pipe routes, and as a Statutory Authority had the right to dig up the road to maintain them. Mercury used them as cable ducts, so the spread of modern telecommunications through the City of London followed a Victorian layout...

[LMS2968]

How far back do you take power generation? With a steam engine, is it in the coal mines? With a diesel. is it in the oil well?

 

The boiler is the source of power, the 'engine' utilises the power released to move the train.

[brack]

How far back do you take power generation? With a steam engine, is it in the coal mines? With a diesel. is it in the oil well?

 

The boiler is the source of power, the 'engine' utilises the power released to move the train.

The Sun is the source of power. Everything else is just storage.

 

(Now where did that hydrogen come from)

[jjb1970]

In terms of thermodynamics, the boiler and reciprocating engine or turbine are part of a heat cycle and considered collectively as the engine.

[Coryton]

The Sun is the source of power. Everything else is just storage.

 

Not in the case of nuclear and geothermal power surely? (Not our sun, anyway)

[EddieB]

Modern Key Stage 3 physics introduces the concept of "energy stores"; "work" happens when energy is transferred from one form (store) to another. "Power" is the rate at which energy is transferred.