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Posted (edited)
On 07/03/2020 at 01:49, Steamport Southport said:

 

 

A curve ball would be the Baby Deltic. I know it says steam. But out of the diesel projects it's the most viable.

 

Diesel preservation is the ugly duckling, though not as much as AC electric.

 

However D5705 and D8233 are both original and serve to demonstrate how hard it is to attract funds, let alone new builds.

 

I hope however the Ivatt Diesel Group make it, they have some pretty solid foundations, with 2 bogies, a frame and an original power unit.. long haul but definitely within reach, considering many other mundane parts will be EE standard bits.

Edited by adb968008
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I really can't get enthusiastic about building copies of old designs. The attraction of preserved items is the history and heritage they represent. If people want to build a new steam locomotive I would much rather see something like the 5AT built.

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Posted (edited)
On 30/03/2020 at 07:33, jjb1970 said:

I really can't get enthusiastic about building copies of old designs. The attraction of preserved items is the history and heritage they represent. If people want to build a new steam locomotive I would much rather see something like the 5AT built.

 

 

Do you mean this monstrosity?

 

image.png.2bbcb419ce7d19f4764313464c742521.png

Edited by 6990WitherslackHall
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1 hour ago, jjb1970 said:

I would much rather see something like the 5AT built.

 

"Just" an updated Standard 5, with a degree of Collet type streamlining. 

https://en.wikipedia.org/wiki/5AT_Advanced_Technology_Steam_Locomotive

 

It'd be nice to see something like that too but not enough people were captured by the project, unlike the creation of new examples of classes that didn't escape the gas axe.

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6 minutes ago, Hroth said:

 

"Just" an updated Standard 5, with a degree of Collet type streamlining. 

https://en.wikipedia.org/wiki/5AT_Advanced_Technology_Steam_Locomotive

 

It'd be nice to see something like that too but not enough people were captured by the project, unlike the creation of new examples of classes that didn't escape the gas axe.

 

such as W1 No. 10000 "hush hush" probably something the A1SLT would recreate.

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8 hours ago, jjb1970 said:

I really can't get enthusiastic about building copies of old designs. The attraction of preserved items is the history and heritage they represent. If people want to build a new steam locomotive I would much rather see something like the 5AT built.

Depends on the project. If the proposal is something significantly different from what's survived then it's much more interesting than yet another GWR 4-6-0.

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On 28/03/2020 at 00:35, adb968008 said:

I hope however the Ivatt Diesel Group make it, they have some pretty solid foundations, with 2 bogies, a frame and an original power unit.. long haul but definitely within reach, considering many other mundane parts will be EE standard bits.

 

Whilst the innards of the Ivatt rely a lot on English Electric components, I believe the hardware was more "Derby". Probably more of an ancestor of the BR/Sulzer type 4s.

 

One significant difference between the Ivatt twins and the more recent mainline diesels was the braking system. The huge majority of diesel locos over the years have relied on compressed air to apply the loco brakes, with a proportional valve to apply the train brake. The Ivatts however had a vacuum cylinder at each end of the central underframe area which presumably applied pull rods and beams to the bogie mounted brake shoes.  Quite how the IDG intend to design their braking system will be interesting, particularly using the EM2 bogies.    

 

Will be an interesting loco when completed.  

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23 hours ago, Covkid said:

 

Whilst the innards of the Ivatt rely a lot on English Electric components, I believe the hardware was more "Derby". Probably more of an ancestor of the BR/Sulzer type 4s.

 

One significant difference between the Ivatt twins and the more recent mainline diesels was the braking system. The huge majority of diesel locos over the years have relied on compressed air to apply the loco brakes, with a proportional valve to apply the train brake. The Ivatts however had a vacuum cylinder at each end of the central underframe area which presumably applied pull rods and beams to the bogie mounted brake shoes.  Quite how the IDG intend to design their braking system will be interesting, particularly using the EM2 bogies.    

 

Will be an interesting loco when completed.  

Without drawings to hand, but thinking of the front cab windows of the Ivatt "Twins", are they close to what became standard EE, or perhaps the Peaks? Bearing in mind that the latter were a Derby design.

 

Apologies for even more 'thread drift', but I do wonder if some salvaging of parts of one or two 'no-hopers' might be in order...

 

Mark

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On 09/03/2020 at 11:42, PenrithBeacon said:

After a loco stops the superheated steam is discharged to atmosphere and the superheater cools. It takes time, once the engine is moving again to get the superheater back up to temperature, say about 15mins. This cycle costs in terms of fuel consumption and on most heritage lines superheating isn't worth it. There are exceptions.

Are you for real?  Superheat most definitely is worth the rather limited complications.  If you have any doubts, go look at what Julia is doing on Traction Talk, or read The Red Devil, or even better, point me to any post 1920 loco that wasn't superheated...even on road steam, better performance from a Garrett wagon with superheat than without...

 

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PenrithBeacon has a valid point. The mass of the superheater, which includes the header as well as the elements, takes time to warm up, and 15 minutes is a figure often quoted. Until it reaches temperature, it adds nothing to the energy in the steam but diverts heat away from evaporation. As it heats, so the steam temperature and energy therein rises and the engine begins to perform as designed. This was an issue with trains out of Euston (and probably other such termini) as drivers were faced with a continuous climb all the way to Tring with a cold engine, and the effects made the gradient more formidable. The superheater would start to produce hot, dry steam about the same time the summit was passed.

 

Shunting engines and those intended for branch line work tended to have saturated boilers right up to the end. I recall a debate about superheated engines on preserved lines, and it was suggested that the superheater be blanked off, or if new tube plates were needed, the superheater be eliminated, as saturated boilers would be better in preservation conditions.

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Posted (edited)
2 hours ago, LMS2968 said:

 As it heats, the steam temperature and energy rises and the engine begins to perform as designed. This was an issue with trains out of Euston (and probably other such termini) as drivers were faced with a continuous climb all the way to Tring with a cold engine, and the effects made the gradient more formidable.

I guess that was a nightmare for drivers and firemen.

Edited by 6990WitherslackHall

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7 hours ago, peach james said:

Are you for real?  Superheat most definitely is worth the rather limited complications.  If you have any doubts, go look at what Julia is doing on Traction Talk, or read The Red Devil, or even better, point me to any post 1920 loco that wasn't superheated...even on road steam, better performance from a Garrett wagon with superheat than without...

 

Yep, I'm for real, but I'm not appreciating North American insults. My comments were about superheating in British heritage railway conditions not out on the mainline.

Having said that the use of the superheated Fowler 2-6-2T on suburban duties, where there would be a station stop every 15 minutes or so did nothing for its already fragile reputation; it just couldn't get its superheater up to temperature so it was one of the reasons it performed badly on these services.

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1 hour ago, 6990WitherslackHall said:

I guess that was a nightmare for drivers and firemen.

The heaviest trains, usually the overnights, were often diagrammed for a pilot as far as Rugby to assist on the climb. It was often a Fowler 2P, which was useful as far as the summit, but from there to Rugby would have to be pushed along by the train engine. Many train crews would have preferred to tackle the climb unassisted  and do without the 'help' between Tring and Rugby.

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Just now, LMS2968 said:

Many train crews would have preferred to tackle the climb unassisted and do without the 'help' between Tring and Rugby.

 

They would have probably stalled. If i was doing that, i would definitely have the banker. I'm not too sure if trains without the banker managed to get up there (they would have probably done) but it's better to play it safe than risk it.

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10 hours ago, MarkC said:

Without drawings to hand, but thinking of the front cab windows of the Ivatt "Twins", are they close to what became standard EE, or perhaps the Peaks? Bearing in mind that the latter were a Derby design.

 

Apologies for even more 'thread drift', but I do wonder if some salvaging of parts of one or two 'no-hopers' might be in order...

 

Mark

 

It is probably subjective Mark but I tend to "see" a lot more "Peak" in the Ivatt cab fronts than English Electric, but then beauty is in the eye of the beholder !!!

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4 hours ago, LMS2968 said:

PenrithBeacon has a valid point. The mass of the superheater, which includes the header as well as the elements, takes time to warm up, and 15 minutes is a figure often quoted. Until it reaches temperature, it adds nothing to the energy in the steam but diverts heat away from evaporation. As it heats, so the steam temperature and energy therein rises and the engine begins to perform as designed. This was an issue with trains out of Euston (and probably other such termini) as drivers were faced with a continuous climb all the way to Tring with a cold engine, and the effects made the gradient more formidable. The superheater would start to produce hot, dry steam about the same time the summit was passed.

 

Shunting engines and those intended for branch line work tended to have saturated boilers right up to the end. I recall a debate about superheated engines on preserved lines, and it was suggested that the superheater be blanked off, or if new tube plates were needed, the superheater be eliminated, as saturated boilers would be better in preservation conditions.

 

8 hours ago, peach james said:

Are you for real?  Superheat most definitely is worth the rather limited complications.  If you have any doubts, go look at what Julia is doing on Traction Talk, or read The Red Devil, or even better, point me to any post 1920 loco that wasn't superheated...even on road steam, better performance from a Garrett wagon with superheat than without...

 

1 hour ago, PenrithBeacon said:

Yep, I'm for real, but I'm not appreciating North American insults. My comments were about superheating in British heritage railway conditions not out on the mainline.

Having said that the use of the superheated Fowler 2-6-2T on suburban duties, where there would be a station stop every 15 minutes or so did nothing for its already fragile reputation; it just couldn't get its superheater up to temperature so it was one of the reasons it performed badly on these services.

 

 

This is clearly not a direct similarity but using the North American analogy, perhaps desuperheating a preserved steam loco would be akin to the North American practice of removing turbos from some mainline diesels.  Whilst the lack of a turbo reduces the power available from the diesel engine, the power unit is simplifed, less to maintain thus cheaper maintenance. I don't believe the practice has crossed the Atlantic but there  was a period when diesel locos were being deturbo'd in North America.  

 

Anyway, this is very slightly off topic for the thread title.,       

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4 hours ago, Covkid said:

 

It is probably subjective Mark but I tend to "see" a lot more "Peak" in the Ivatt cab fronts than English Electric, but then beauty is in the eye of the beholder !!!

I agree - there is a definite hint of 'Peak' there...

 

...hmm...

 

Mark

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The new build I am following with interest is the LMS NCC W class

2-6-0 currently being constructed by the Railway Preservation Society of Ireland.

 

Details here.

 

https://www.therailwayhub.co.uk/8088/rpsi-cuts-frames-for-new-build-lms-ncc-w-class-mogul/

 

 

Details of the original W class here.

 

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

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36370147165_eb97381224_b.jpg

 

If you wanted a new build 444t I'd be looking at the wirral, rather than the rather ugly things the met had. Plus if you wanted to talk about things unrepresented in preservation, the wirral railway was one of those pregrouping lines where everything was culled in the 20s.

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Ref: Superheat Temperatures

 

I'll quite happily answer sensible questions- if you have a copy of "The Red Devil", Fig 136 shows fairly convincingly that the time to heat the outlet steam on a superheater on the Class 26 in SAR service is somewhat less than 3 minutes from 200-250 C, then continuing up to 325C by the 15 minute mark.  I am not shocked that it takes time for this to happen- but let's take a look at what is happening to energy in the steam.  By going from 200C to 250C, that is an increase of 90F

 

Steam tables give 1201 btu/lb @ 200 PSI/390F (Sat Temp), and 1239 at 200 PSI/450F, so 38 btu more extractable, or  230 vs 270 btu extractable...so,, 40 btu/lb more extractable heat.    Given that 2544 btu= 1 hp/hr, for each HP generated you need either 9.4 lb steam or 11.4 lb steam to make 1 HP.  Now, colour me silly, but I'd rather boil 2 lb less water per hp/hr.  This is close to a 0 sum game- if you increase the steam temperature (not pressure, though pressure helps), then you reduce the amount of weight of water required.  The further increase shown above to 325C (1313 btu/lb) is most definitely of benefit.  That higher enthalpy means that the loco's power and efficiency are both radically affected by the steam temperature increase.

I'd ask that if you want to have a bash at North Americans, remember, some of us own more steam engines than most preserved railways, and have a diploma in the use of.  They might be smallish, but I own 4 locos, a pair of traction engines (2" and 4"), a steam wagon, and have been messing around with steam for a little while.  I have been involved in some experimental engineering involving the Doble boiler designs, and hold a marine engineering EOOW qualification for Cross Compound Steam Turbine ( 21000 HP), as well as Stationary Engineering (3rd class).

 

If a preserved line honestly thought that removing the superheaters on engines would work, they'd do it- it's far simpler to put a bypass pipe in than a superheater.  Since I am unaware of this ever being done beyond an experimental steam up and down while a superheater was built, I would suggest the practical experience is that any loco that was designed with superheaters works far better with them than without. 

 

My personal experience is like so- that on the 1980-90 Traction Engine we had (2"/ft, freelance), if you didn't have the superheaters, it was a pathetic dog in comparison to having them.  It was bad enough that in 1987 or so, when we blew the spearpoints at Hamilton Museum of Steam Technology, it was worth taking the engine home that night, and fit a replacement superheater overnight.

The other example that I am well aware of with us, is the pair of Caribou (0-8-0, Martin Evan's design) locos.  The one I have has a superheater- 3x 3/16" spearpoints, I think.  The other one had a saturated boiler.  We kept the superheated one, and sold the saturated one...

The size of the engines does make a difference to scale effects and speed of reaction.  However, in full size, I boiled about 8x the output of the largest UK loco/hr, and if you turned down the superheater temperature, it certainly had a measurable, observable effect on steam consumption.  Maximum superheat at work was about 400F (865F limit, 488F sat pressure at 600 PSI steam).

 

I believe, that in any use where the loco is traveling for longer than a couple of minutes, that the effects of superheating are going to outweigh the costs.    The change over distance is probably something like a mile- if the total run is going to be less than a mile, then I can understand why not fitting superheaters, but if the run distance is going to be more than a mile, the costs (superheater elements) are going to be covered by the reduction in water and fuel consumption.  I certainly would not advocate designing a "new build" engine without superheat, it goes against everything I have ever experienced or read.  I believe the number of locos that will only ever run less than a mile, at 25 MPH or lower, are limited.

 

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On 30/03/2020 at 09:24, Hroth said:

 

"Just" an updated Standard 5, with a degree of Collet type streamlining. 

https://en.wikipedia.org/wiki/5AT_Advanced_Technology_Steam_Locomotive

 

It'd be nice to see something like that too but not enough people were captured by the project, unlike the creation of new examples of classes that didn't escape the gas axe.

Superficially yes, but an altogether quite different beast - as the linked Wiki article indicates.  A bit like comparing a Ford Cosworth to a standard Escort.

 

But it was discussed and dismissed on this site around the time the project was suspended.

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ÊUltimately the 5AT would be an exercise in futility insomuch as it would just confirm that if you designed and built a modern steam locomotive it would still be very inefficient and have high operating costs but it would still be interesting. Much more interesting than just building another facsimile of an old design. 

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I have always thought that the problem with the 5AT was that it couldn't possibly have hauled a paying load on the mainline; just too small.

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19 minutes ago, jjb1970 said:

ÊUltimately the 5AT would be an exercise in futility insomuch as it would just confirm that if you designed and built a modern steam locomotive it would still be very inefficient and have high operating costs but it would still be interesting. Much more interesting than just building another facsimile of an old design. 

The new steam locos built by DLM in Switzerland proved that at least in the niche application for which they were designed, steam could be more efficient than both diesel or electric traction.   Note my use of the word niche; the 5AT wasn't designed for a niche application.

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