The Night Mail

[Tony_S]

4 minutes ago, polybear said:

 

How about heating the water with Hydrogen-fired burners?

The Swiss would seem to have had a plan to turn steam engines into electric kettles since about 1904. During WW2 domestic coal shortages produced the machine described in the following link.

http://www.douglas-self.com/MUSEUM/LOCOLOCO/swisselec/swisselc.htm

 

Edited October 30, 2021 by Tony_S

[SM42]

1 minute ago, polybear said:

 

How about heating the water with Hydrogen-fired burners?

 You could collect the exhaust and use a generator powered by  a drive off the axle and a  small wind turbine on the front to create more fuel

 

Genius!

 

Oh hang on...

 

 

Andy

[Northmoor]

1 hour ago, Happy Hippo said:

Because even with the vast leaps in technology and science, the physical efficiency of a reciprocating steam engine drops far below what we would want in this ever increasing green environment we live in.  

 

What we should be looking at is increasing the efficiency of electric locos, which believe it on not, aren't as efficient as a diesel!

 

 

I don't know where you've got that from.  Yes, there's the argument about the efficiency of the thermal power station that generates the electricity (solved with non-fossil fuel resources), but a big diesel engine is about 35-40% efficient, big electrical equipment is about 80% efficient (so a diesel loco is perhaps 28-32% efficient).  Also consider that these figures are for when it's actually hauling a train; while the diesel is 0% efficient when it's standing idling, the electric loco remains efficient as it is barely drawing any amps at all. 

[Dave Hunt]

19 minutes ago, PhilJ W said:

According to Wiki diesel did use peanut oil in his first engines. The first oil engines used paraffin as fuel. 

https://en.wikipedia.org/wiki/Herbert_Akroyd_Stuart

 

Diesel’s original proposal was for a coal dust fuelled engine but due to problems of handling the stuff he substituted peanut oil for the first prototype to run successfully. The switch to paraffin was, IIRC, due to lobbying by the mineral oil industry.

 

As Jamie stated, even with advanced technology it would be virtually impossible for a reciprocating steam engine to approach the efficiency of an IC type.

 

Dave

Edited October 30, 2021 by Dave Hunt
Damned predictive text rubbish again

[SM42]

2 minutes ago, Dave Hunt said:

 

Diesel’s original proposal was for a coal dust fuelled engine but due to problems of handling the stuff he substituted peanut oil for the first prototype to run successfully. The switch to paraffin was, IIRC, due to lobbying by the mineral oil industry.

 

As Jamie stated, even with advanced technology it would be virtually impossible for a reciprocating steam engine to approach the efficiency of an IC type.

 

Dave

 

Why  not use the steam to drive turbine and  generator to power an electric motor. 

A sort of steam electric 

 

Andy

[DenysW]

All covered and hacked about in the imaginary locomotives thread.

 

Sadly, thermal efficiency is independent of the fuel. It's simply the fraction of the heat available that gets covered into useful work. External combustion is also limited by the high latent heat to boil the water, and you throw that away unless you condense the steam in a way the recovers this. Attempts to do this generally not very successful - e.g. the Erie Triplex locos.

 

Isn't Rugby the sport where they haven't yet worked out life is easier when you play with a ball that bounces true?

[Happy Hippo]

15 minutes ago, SM42 said:

 

Why  not use the steam to drive turbine and  generator to power an electric motor. 

A sort of steam electric 

 

Andy

And generate the steam using a nuclear reactor like  they power nuclear subs and aircraft carriers.

 

Can you imagine the uproar at that.

 

It's almost as ludicrous as flying cars.

 

They are great in theory but can you imagine the masses getting hold of them.  If you think that a high proportion of UK drivers are poor (which they are) then can you honestly say that they would be capable of controlling going up and down as well as forwards/backwards/left and right, as well as having meaningful relationship with ATC?

 

I took the information about efficiency from the TRB site which I got to by typing into the search engine 'efficiency of a steam engine'.

 

They state:

 

 'The efficiency of the steam locomotive has been given as 11 percent and that of the electric locomotive as about 20 percent. Neither value compares favorably with the 28 percent estimated for diesel locomotives, the ratios being 1.82 for electric/steam, 1.4 for diesel/electric, and 2.55 for diesel steam traction. On the score of fuel consumption the diesel engines are not so much better than electric locomotives. For example, when pulling a 350-ton train at 70 mph on the level, the electric locomotive must develop some 900 hp at the wheels, compared with 1,100 hp required from the heaviest diesel-electric locomotive, so that the ratios of efficiencies will be only 1.145 whilst parity will be attained at 70 mph with a trailing load of about 175 t. also on the level.'

 

I have no idea whether they are sponsored by EMD or another Diesel loco manufacturer, but since it was not Wikipedia, thought it was probably relevant.

 

 

 

 

[Dave Hunt]

2 hours ago, Happy Hippo said:

Anyone who has  actually worked with and  had to maintain steam locos  will know that tight tolerances and exact fit ups are a recipe for disaster.

 

I had an uncle who was a Crewe apprentice in the 1940s and at one time was involved in preparing and then maintaining a locomotive (a Black Five IIRC) for the Rugby testing plant. He told me that they spent ages setting up the valve gear to the tolerance of a gnat’s  tadger only to observe when the engine was working on the rollers that the flexing in the motion bracket etc. was making something of a mockery of all their efforts.

[jamie92208]

36 minutes ago, SM42 said:

 

Why  not use the steam to drive turbine and  generator to power an electric motor. 

A sort of steam electric 

 

Andy

It's been done several times over the years but none of them have been commercially succesful.  IIRC UP had 2 in the 30's.  Once again the G forces are against you for reliability. The equipment is just not robust enough to withstand the constant 10G shocks.  The first pacers sufferred from a form of this when lorry/bus technology was used to keep costs down and relays kept dropping out as they weren't bolted in. 

 

Back to steam turbines.  That was what Jawn Henry on the Norfolk snd Western used and I believecthat the C & O had one as well. The turbines genersted electricity for conventional traction motors.

 

As to the supposed inneficiency of electric locos, I believe that the current problems in the UK are due to the high markup charged by Network Rail for current from the overhead.

 

Jamie

Edited October 30, 2021 by jamie92208

[Dave Hunt]

28 minutes ago, SM42 said:

 

Why  not use the steam to drive turbine and  generator to power an electric motor. 

A sort of steam electric 

 

Andy

 To maximise the efficiency of a system such as you describe, the steam turbine/generator needs to be very large with as big a temperature gradient as possible between inlet and exhaust - pretty much like a power station in fact. Then you can distribute the electricity generated to remote electric motors via overhead wires or third rails. Oh, hang on, that’s how electric trains work isn’t it?

 

Dave

 

[Happy Hippo]

14 minutes ago, Dave Hunt said:

 

I had an uncle who was a Crewe apprentice in the 1940s and at one time was involved in preparing and then maintaining a locomotive (a Black Five IIRC) for the Rugby testing plant. He told me that they spent ages setting up the valve gear to the tolerance of a gnat’s  tadger only to observe when the engine was working on the rollers that the flexing in the motion bracket etc. was making something of a mockery of all their efforts.

If you cannot get an engineers steel ruler between the crosshead slippers and the top and bottom slide bars, then it's too tight!

 

Somewhere I'm sure I've read about steam locos having been built in factories that previously been manufacturing munitions (so extremely close tolerance work) during WWII, produced locos that had a tendency to seize up on the road.

 

I seem to recall Aster/Fulgarex having a similar problem with their prototype for the Gauge 1  Gresley A4 Pacific.  The use of dissimilar materiel in the cylinder department leading to the piston expanding at a higher rate than the cylinder block.   

 

As you can imagine it was all stop, until things had cooled down.

Edited October 30, 2021 by Happy Hippo
spellnig

[Oldddudders]

4 hours ago, JohnDMJ said:

Class 73s were the first hybrids IMHO.

Yes, in the UK - but the New Haven had been running a fleet of FL9s since 1956. 

[DenysW]

I've seen it claimed that L.D. Porta holds the record for measuring the least efficient steam locomotive of all, based on losing 96% of its steam to leaks.

[Happy Hippo]

21 minutes ago, DenysW said:

I've seen it claimed that L.D. Porta holds the record for measuring the least efficient steam locomotive of all, based on losing 96% of its steam to leaks.

Sounds like anything out of my workshop!

[Florence Locomotive Works]

6 hours ago, iL Dottore said:

Okay, time to throw out a pumpkin-shaped Halloween-themed fragmentation grenade disguised as a question:

 

With the improvement in materials and materials technology, CAD and CND manufacturing and a better understanding of the science behind it all (metallurgy, thermodynamics, etc) and applying all that to the construction and production of frames, wheels bearings, boilers, pistons and cylinders, etc., could you build a modern steam locomotive that is lighter, more efficient, faster and less polluting than their pre-1970s forebears?

 

The second (rather nasty) part of the question is could you then make such a locomotive emit -  per passenger mile - less CO2 than a diesel or electric locomotive equivalent? (taking into account the cost and method of producing electricity).

 

And your bonus for 10 is: could you also come up with a process to efficiently recycle the usual waste produced by steam locomotives - ash and clinker - and turn it into a useful product (which would be…?)

 

(These questions were inspired by the postings of Dave Hunt and others above)

Yes absolutely you could, I have spent a decent amount of time looking I into such a thing.

 

 

A good starting ground would be a well sorted American 4-8-4 (preferably Frisco 4500 as it has an oil fired tender and is in stable condition) with cast steel frame, so that roller bearings could be fitted if they haven’t already. This engine would then be sent off to technical college somewhere where the students could build on the work of  Andre Chapelon and LD Porta to improve the the thermodynamic efficiency of the engine to a much higher standard. This has already been done in Switzerland on a almost completely rebuilt DB Br 52 2-10-0. It’s speed was increased from a max of 50 mph to nearly 80.

 

However there is still much to be made in improvements, most notable they fitting of a Chapelon designed ACFI feed water treatment system, which increases efficiency by some margin. Work would also need doing to fit either a Lempor, Kilchap or Lemprex exhaust system to the engine. 
 

Porta also carried out unfinished work on using alternative oil fuels in locomotives which looks mighty promising.

 

 

On emissions: According to the company who rebuilt the 2-10-0 (they are the only company in the west dealing with steam on an industrial scale, mostly paddle steamer engine rebuilds) they were able to get the emissions of their engine to 80% below that of a modern diesel. Now I’m not entirely sure that’s possible, but it would be great if true.

 

 

Methane firing would also be excellent especially in my part of the world as the stuff is literally leaking out of the ground in my backyard, and it burns very clean for a gas. A new design of firebox would have to be made for it though.

 

I also have an associate in the northeast who believes he has some pretty nifty compounding design that could solve some problems.

 

This paper (which is really worth a read) answers a lot of questions to. Graphs and diagrams are included to. Get a mug of tea first.

 

https://www.internationalsteam.co.uk/trains/newsteam/modern50.htm

 

In the end though it would not be possible to match the efficiency of a diesel or electric. You could maybe get close, and it might be better for the environment, but it isn’t possible. The main thing going for it though is that reciprocating engines create jobs.

Edited October 30, 2021 by Florence Locomotive Works

[AndyID]

It's all Carnot's fault.

 

https://en.m.wikipedia.org/wiki/Carnot's_theorem_(thermodynamics)

 

 

 

 

 

Edited October 30, 2021 by AndyID
Failure to proof read!

[pH]

There were two UK attempts at steam-electrics:

http://www.douglas-self.com/MUSEUM/LOCOLOCO/reidrams/reidrams.htm

 

http://www.douglas-self.com/MUSEUM/LOCOLOCO/armstrongturbine/armstrng.htm

 

 

 

 

[PhilJ W]

Many gas turbine engines can run on a fuel/water combination. As much as 20% fuel/80% water. The water is injected between the combustion chamber and the turbine, hence the vapour trails from jet aircraft visible on a clear day. This IIRC is only used on take off or when extra power is needed. The reason it isn't used full time is water requires more space and is heavier than kerosene jet fuel.

[Happy Hippo]

33 minutes ago, PhilJ W said:

Many gas turbine engines can run on a fuel/water combination. As much as 20% fuel/80% water. The water is injected between the combustion chamber and the turbine, hence the vapour trails from jet aircraft visible on a clear day. This IIRC is only used on take off or when extra power is needed. The reason it isn't used full time is water requires more space and is heavier than kerosene jet fuel.

It's nothing new as both the Allies and Axis powers were experimenting with using water to boost combat power for engines during WWII.

 

Harrier V/STOL aircraft also had  a water injection system, used I believe during the vertical take off/ landing sequence which gave about 90 seconds of lower turbine temperature and higher thrust.  This would help if the airframe in question required vertical thrust at higher all up weights (AUW).  I think the 90 second limit was determined by the water tank  capacity!

 

Edited October 30, 2021 by Happy Hippo

[Happy Hippo]

Well done to the All Blacks, even though it was a foregone conclusion.

 

The Penderyn is much depleted, as readers will have accepted as the second foregone conclusion.

 

 

[AndyID]

4 minutes ago, Happy Hippo said:

It's nothing new as both the Allies and Axis powers were experimenting with using water to boost combat power for engines during WWII.

 

Harrier V/STOL aircraft also had  a water injection system, used I believe during the vertical take off/ landing sequence which gave about 90 seconds of lower turbine temperature and higher thrust.  This would help if the airframe in question required vertical thrust at higher all up weights (AUW).  I think the 90 second limit was determined by the water tank  capacity!

 

 

Not unlike those compressed air water rocket toys. Brilliant example of F=ma

[Tony_S]

7 minutes ago, AndyID said:

 

Not unlike those compressed air water rocket toys. Brilliant example of F=ma

Very popular with the physics classes I used to teach. We did go outside to launch them. 

[Northmoor]

13 minutes ago, Happy Hippo said:

It's nothing new as both the Allies and Axis powers were experimenting with using water to boost combat power for engines during WWII.

 

Harrier V/STOL aircraft also had  a water injection system, used I believe during the vertical take off/ landing sequence which gave about 90 seconds of lower turbine temperature and higher thrust.  This would help if the airframe in question required vertical thrust at higher all up weights (AUW).  I think the 90 second limit was determined by the water tank  capacity!

 

Yes and the vapour trail has nothing to do with injecting water into the combustion chamber, it's to do with the water (+CO2) from burning hydrocarbons).  The samll amount of water on the Harrier was as you say for cooling, because with little or no forward motion, you've much less air cooling the turbine.  Water injection into the exhaust has been used on high performance engines (the last race 2-strokes), but I think that was to do with reducing back pressure to gain power.

[Tony_S]

12 minutes ago, Happy Hippo said:

Well done to the All Blacks, even though it was a foregone conclusion.

 

The Penderyn is much depleted, as readers will have accepted as the second foregone conclusion.

 

 

My phone and iPad kept pinging about Australian wickets falling so I watched the T20 cricket match from Dubai. All over quite quickly. 

[Tony_S]

55 minutes ago, PhilJ W said:

ence the vapour trails from jet aircraft visible on a clear day.

Surely the vapour trails seen from high altitude aircraft are from condensation of the water produced by combustion of hydrocarbon fuels and oxygen?