US Army Locomotives with Lempor Exhaust

whodom · **Posted:** Mon Sep 15, 2014 6:23 am

Jeff Lisowski wrote:

While we are on the subject; does anyone have a thought on why Lempor exhaust or other exhaust modifications don't seem to be as popular here in the US as they are overseas?

Jeff- Starting in the 1980's (?) Nigel Day (originally working with Shaun McMahon) oversaw numerous Lempor installations on steam locomotives on tourist railways in the UK.

My guess is the large number of Lempors in the UK can be attributed to the fact that there are so many tourist railways operating steam, they have a real need for reducing fuel consumption and improving performance, and there was someone there that was knowledgable of the design, fabrication, installation, and tuning of Lempor exhausts (Nigel) to promote their use.

It's worth noting that the full-size Lempors in the US were also done by Nigel, including 2 at the Grand Canyon and one at Mt. Washington.

Dave · **Posted:** Mon Sep 15, 2014 9:15 am

Jeff Lisowski wrote:

While we are on the subject; does anyone have a thought on why Lempor exhaust or other exhaust modifications don't seem to be as popular here in the US as they are overseas?

A battle I'm almost giving up on fighting......

Ignorance is a part of it. Acceptance of "good enough" another part of it. I'm dealing with people who don't understand how the old school designs work, just have blind faith in them since theoretically smarter than us people designed them that way 100 years ago. They did work well enough, of course.....and how to quantify "better" without expensive and also confusing testing and mensuration? So, you come along with plans and designs for something that is just a part of "new and improved" which mathematical models (also similar to black magic) suggest will do more work with less inefficiency, and try to apply it to a large complex model with a lot of things happening and in flux at the same time......

Then you build a program for including many improvements in an overhaul which, if executed properly, can reduce operating and maintenance costs by perhaps 20% IF OPERATED CORRECTLY since just a better exhaust isn't a panacea for inefficiency standing alone. Now, you have greater not understood mysterious mechanical alterations to also not understood but trusted and time tested original technology, and the people have to learn how to operate for efficiency? Some are only marginally able to operate for getting the train over the line, but how good can you get if you work maybe 10 days per year?

The conclusion I'm reaching is that working for sustainable steam by increasing efficiency and operating cleanly and efficiently is not going to be possible for the ordinary, small volunteer operated museum or tourist line. It requires staff that is there working a lot to build and maintain true expertise, infrastructure, standards and practices that require a higher standard of maintained experience and body of knowledge......and really good, well meaning guys who love what they do and do it simply for the intrinsic reward in spare time with full lives to live besides, just aren't going to be able to pull it off.

And, I haven't even touched on the "sacred original fabric" or "not invented here" reactions. Both of which are, of course, bogus in the context of operating which by definition consumes and comfortably entrenched ignorance as a religion rather than a reality.

So, perhaps we need to look first at our operating and management model if we want to build for sustainable steam programs. Which means we need to look at our entire business model related to just that part of it. Which is a good thing and probably overdue for about 98% of us anyhow.

dave

Alexander D. Mitchell IV · **Posted:** Mon Sep 15, 2014 11:07 am

The fact remains that, for most excursion lines in the United States, they're not running anywhere near as intensive a service as to warrant such investment, and many of the ones that are--Grand Canyon, Cuyahoga Valley, Mt. Washington, Conway Scenic, etc--have gone partially or even mostly/completely diesel.

If the Grand Canyon wanted to intensify its steam service, 4960 or SP&S 539 would be an ideal candidate for such a refit. Strasburg seems another possibility. Maybe the Disney operations, and we've already been subjected to rumors of "dieselization" of their operations. Durango & Silverton?

The Keighley & Worth Valley Railway, where 5280 operates, has five steamers ready to run, four more under active overhaul, and FOURTEEN MORE stored awaiting overhaul or preserved as museum pieces. And we're not just talking a bunch of rusted-out 0-4-0T's in the latter category, but a 2-8-0, a 4-6-0, a 2-6-4T, several big 0-6-0's, etc. Many of the noted U.K. excursion lines--Severn Valley, North Yorkshire Moors, etc.--have similarly large "stables".

Dave · **Posted:** Mon Sep 15, 2014 11:55 am

Keighley and Worth Valley is Strasburg cubed.......and serves a time capsule branch line with commuter train schedules and does it well, day in and day out. That's undoubtably intensive......but the capitalization cost is just one factor. Life cost VS initial cost is the issue - do you want to take a big bite up front or get nibbled to death over 15 years? Sometimes there's a choice, sometimes no choice, and sometimes we set ourselves up in situations in which we think we have no choice based on our perceptions, or inability to adapt to workable models for long term sustainability.

Everybody's mileage may vary....but we can all make decisions which can impact what parameters define the range of our potential mileages possible.

Universally, however, objects in mirror are closer than they appear.

dave

JJG Koopmans · **Joined:** Sat Oct 22, 2011 5:07 am **Posts:** 82

Jeff Lisowski wrote:

While we are on the subject; does anyone have a thought on why Lempor exhaust or other exhaust modifications don't seem to be as popular here in the US as they are overseas?

Well, a Lempor appears to be well performing! However, having said that, for the last 30-odd years there has only been hands-on experience and not any systematic test program. Locomotive owners might be aware of that. UP 3985 took care of a lot of bad publicity while the poor explanation of the fluid dynamics of a Lempor do not help either.
As for the NIH effect, you folks should be more aware of the tests of Everett Young ofIllinois University: "A Study of the locomotive front end ; including tests of a front-end model". It is on-line these days: https://www.ideals.illinois.edu/handle/2142/4435
Back in 1933 he showed experimentally the equivalence of a double length chimney and the effect of 4 orifices only. So some extra thinking and an expenditure of maybe 100 dollar for another blast cap could already save you a lot of coal and water!
My 2 eurocents!
Kind regards
Jos Koopmans

JJG Koopmans · **Joined:** Sat Oct 22, 2011 5:07 am **Posts:** 82

The problem is that one cannot really change to a Lempor without a visual modification.
The issue is that instead of a 4 to 6 degree tapered chimney a diffuser of about a 10 degree included angle is used to maximise performance. As a consequence the hole in the smokebox should be larger to allow for the larger chimney exit. Of course the Lempor can be tailored into a smaller size, however, the orifices decrease in diameter also in that case so that it carries a price tag in the form of a larger back pressure which was not wanted to begin with!
However, a locomotive which has a wide chimney, over 3 times the orifice diameter, has little taper and ample inside length would be a prime target for a low-cost change afaiac.
Kind regards
Jos Koopmans

Dave · **Posted:** Tue Sep 16, 2014 8:46 am

Jeff Lisowski wrote:

But the question begs; if something like a Lempor exhaust could be done with minimal "external" visuals changing and better steaming...why not do it?.

It can. but not as a strict Lempor....there are compromises made to the Lempor design to fit it into historic structures. Performance still improves, although not as much as if done completely. Dr koopmans and others have been very helpful in working out two such compromises for locomotives I know about, neither of which have been retrofit (one isn't really a retrofit as the whole internal exhaust system is gone).

Likewise, there's a limit to the improvements that can be invisibly made to steam passages within the valves and cylinders, although you can make a lot of improvements in valve performance and blowby reduction internally, and using multiple stacked metallic packings can substantially reduce blowby along the rods. Providing better thermal insulation around the boiler, steam pipes and cylinders is also very possible.

Which doesn't mean it isn't worthwhile to make these improvements if you have to do heavy work anyhow.....the cost is much more marginal since all the internal components are being overhauled anyhow. Done as running repairs....not as easy to justify.

dave

whodom · **Posted:** Fri Oct 03, 2014 8:28 pm

Andrew Durden wrote:

Anyone heard any further updates on the performance of this loco?

http://www.rypn.org/forums/posting.php?mode=quote&f=1&p=220606#

Andrew- I received this detailed reply from John Hind of the 5AT Group describing the performance of the Lempor on the Keighley & Worth Valley Railway #5820:

Quote:

Attached are the quotes I promised from three different people - 2 drivers and a fireman. Apologies for waiting so long to reply but I was waiting some dimensions from one of our team who does our CAD - he has been away on holiday. I have also included some pictures to help explain some things - a pictures says a thousand words!.

First some background about the Keighley & Worth Valley Railway:-

It is just under 5 miles long and climbs all the way from Keighley to Oxenhope at an average gradient of 1 in 76 (1.31%), with a ruling gradient of 1 in 58 (1.72%). Loads are normally 6 coaches (trailing load 219 tons), though for special occasions 10 coaches (trailing load 365 tons). Maximum speed is limited to 25 mph (legal limit applied to all Heritage/Tourist Railways in the UK.). It is one of the major tourist attraction in the area.

The railway operates most weekends of the year and daily during the summer months. The website is http://www.kwvr.co.uk/

Some background about the engine:-

The engine was imported from Poland in 1992, but had been fitted with a longer chimney by Polish Railways, this had to be reduced in height to fit the UK loading gauge . Initially it had a reputation as poor steamer, to counteract this a bar was fitted across the blast pipe - known in the UK as a 'Jimmy' (picture attached). At the last overhaul we were asked to see whether we could improve its steaming and coal consumption. To answer one of the questions on RYPN, it is fitted with power operated firehole doors.

We have not had chance to test the performance of the Lempor, so can't give any figures. We are waiting for a date from the railway, who run daily in the summer and only weekends in the winter, so finding a date for running test trains when crews are available and that fits with everyone's diary is proving to be tricky. The only thing we can do of for now is quotes from crews :-

"It steams well under all load conditions, and stopping it from blowing off is more of an issue. It will steam quite happily on 4 or 5 coach loads at around 25% cut-off, and equally well on 6 or 10 at commensurately longer cut-offs." He has it fired with a saucer shaped fire, thin in the centre, and runs mainly with the fireman's side damper open (drivers side is difficult to reach) or on lighter loads, neither, as enough primary air gets in around the gaps etc.

"I had my first full day on 5820 today. We worked the dining set which is a heavy 6, (included two Pullmans and the kitchen car). The exhaust system performs well in these conditions. We did notice that it does pick the steam rate up if you give it some stick. Anyway, it's a very competent loco in all respects, easy to fire, easy to drive and well on top of anything we are going to give it to do."

"It really is effortless to fire, thin and bright and steams like a witch, rides well, goes well, sounds well.".

After the war, S160's were used on French Railways and tested on a static test plant - there are some basic performance figures quoted in Chapelon's book 'La Locomotive a Vapeur' Page 411 of the english language re-print, which describe improving their steaming by reducing the nozzle area from 130 cm2 to 99 cm2. By way of comparison the nozzle area of 5820 has been opened upto 160 cm2 and its steaming has been improved. Opening up the nozzle area reduces back pressure, which increases power. A feature of this installation is that we can swop the nozzles to tune the exhaust system for optimum performance - to date we have not had to do that.

From pictures I have seen, most railways tried to improve steaming by modifying chimneys either by lengthening or increasing diameter - the Fort Eustis S160's look to have had their chimneys lengthened.

As built the the original chimney diameter was 410 mm (16.14 inches) dia , the exit of the Lempor is 459mm (18.07 inches) dia. In the UK, Heritage Railways use vacuum brakes (the engine itself is airbraked). The vacuum is created by a steam powered ejector and this exhausts through an annular chamber that surrounds the Lempor. Included in the pictures is a shot of the top of the smokebox during the assembly of the Lempor before it was welding in place, this shows the vacuum ejector exhaust surrounding the Lempor. The picture also shows the alignment jig to ensure that the mixing chamber and diffuser assembly is aligned with the blast nozzles. The OD over the vacuum ejector exhaust is 485 mm (19 inches) and then for aesthetics we put a 'half round' lip round the chimney. The exhaust from the vacuum ejector does not contribute to the Lempor performance.

The 5AT Group website gives more background and pictures in a downloadable PDF. http://5at.co.uk/index.php/news/44/269/ ... haust.html.

As Jos Koopmans has said the mixing chamber and diffuser arrangement was one of the chimney configurations tested by Young in the USA in the 1930's. The Lempor exhaust uses the mixing chamber and diffuser arrangement plus multiple convergent divergent blast nozzles.

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