hunslet gas producer modifications

I know that several Austerities locos were re built by Hunslet as gas producers, can anyone with experience of these locomotives explain what the idea was, and how effective the modifications were in traffic, for instance ,was it an improvement over the standard austerity loco or a complete waste of time , one of our trustees is very keen to see Antwerp rebuilt as a gas producer and whilst i dont know the difference in steaming efficientcy i would not myself be in favour if it leads to an inferiour engine

 

A detailed article on applying a GPCS on the Kirklees Light Railway (15" gauge) can be found on the friends' website - seems to have been successful there. More articles about GPCS and other 'modern steam' on Martyn Bane's website, including information about the modified Austerities (including some pictures of Antwerp).

It would be good to see a GPCS Austerity running again. They seem to have been little used in preservation. I've wondered if this was due to the complexity of the system. Or perhaps GPCS made the locos so good that the NCB effectively wore them out, due to intensive use, this condition also making them low priority candidates for restoration once preserved.

 

Here's a more direct link to the GPCS page on Martyn's excellent site. http://www.martynbane.co.uk/modernsteam/ldp/austerity/portaausterity.htm

I have fond memories of working Fred at the KWVR - always a reliable performer - even I could get it to steam OK - and bunking the coking plant at Smithywood near Sheffield to see the last gasps of the pair based there in the early 70's.

 

Martin,

I would suggest you read Industrial Railway Record 196 which has an excellent article on modifications made to NCB locos.

The Hunslet stoker fitted locos (Hunslet didn't call them Gas Producer locos) were tested by BR and the conversion doubled the steam rate from 6000ibs to 12,000 ilbs per hour, made the engines less sluggish and gave a power output of 898hp. The main reason for the equipment though was not to increased power but reduce smoke and to keep steam in use longer. There are interesting comments from Bickershaw drivers that said when fired on small coal as designed they were ''mad buggers'' and lets face it tank engines rarely worked harder than at Bickershaw. Others didn't get on with them so well but this may have been down to training or because the stoker unit was not suited to colliery work.

Antwerp would certainly look fine in maroon at Folkestone and the gas producing system may keep the neighbours happy.

Hope this assists,

David

 

This seems to be the main issue with GPCS it needs the right kind of coal, not just the type but the size needs to be consistent as well. On the Festiniog the system was trialled on Linda http://www.martynbane.co.uk/modernsteam/pg/linda/frlinda.html. The system worked fine with the loco working right at the limit just like it did on oil. The difficulty was sourcing the perfect coal for 1 engine while the rest were burning abundent and at the time cheap waste oil. I belive that River Esk on the R&ER has also had its GPCS equipment removed for simalar reasons.

It's obviously not an issue for the NCB and the KLR seem to be fine with it but then all their locos run the system and with no disrespect intended they don't run the kind of services that the R&ER and FR do.

Tim

 

The main trouble with the Austerity conversions was the stoker. In service, this often gave trouble, for whatever reason (and there were several). Once the stoker packed in, it was down to hand firing and the whole principle of the system has gone by the board, as you are effectively back to a conventional coal burner. The Kylchap blastpipe may well still be there but that is only half of the story. When Hunslet resurrected 3168 (now Wheldale on the E&BSR)in 1980, it ran well and proved that the system did all that it was intended. When the trials were over, the loco continued in service at Wheldale but the stoker soon fell into disuse due to being jammed and no Hunslet fitter there to sort it out.

The Hunslet system was essentially designed to burn coal smokelessly and this it did. Without the stoker, which pushed the coal under the firebed and thus consumed the smoke, the principle was effectively lost.

In restoring Antwerp, you have various choices:
1) As a standard Austerity with conventional blastpipe
2) As a standard Austerity but with a Kylchap blastpipe
3) As a stoker fitted Austerity with a Kylchap blastpipe and additional air inlets to the firebox.
4) As a stoker fitted Austerity with a conventional blastpipe and additional air inlets to the firebox.

 

the main drawback as i can see it is, you need to have the right size of coal, and the stoker has to kept well maintained, otherwise as stated its not worth fitting , richard moffet is very keen on gas producer systems, but im a bit more practical minded , A standard austerity will steam ok on normal sized coal, which i would guess would be easier and cheaper to get I can see the benifit of fitting better drafting and a more effective blastpipe.
For me , the issue is if we had to run with gas producer systems it would have to be because we were made to by residents complaining rather than because someone thinks its a good idea, given the problems in traffic that gas producers could cause , and as in preservation, most were taken out or not used , which to me says its not practical to have them

 

Whilst only having a limited knowledge of the application to the Austerities, I do have first hand experience with the locos at the KLR. This is the GPCS in its simplist application with ashpan steam, modifications to the firedoors to allow decent amounts of secondary air but without the hollow side stays. On the KLR we have burned various coals with it ranging from Eagle Energys finest european stuff, CPLs Pure Heat reconstituted nuts and to the current Eckington Colliery cheap coal. The only stuff that has caused problems is coke of an unknown source which we used at the Cleethorpes Coast Light Railway with our two smaller locos. The ashpan steam cooled the firebed too much. Our two smaller tank engines have 15 inch square fireboxs, with these we pull trains of up to 9 coaches weighing in at 20 tons (locos weigh around 3 tons) up a 1 in 70 gradient at around 15 mph over a distantance of 3.5 miles. In this distance the railway climbs 220 feet. When running our 1 hour or 30 minute service trains do the round trip in just over 50 minutes. Turn arounds at each end of the line are less than 10 minutes so it is not a circuit in the park. The GPCS is not the only thing that has made the locos consistant performers. Steam circuits and blast arrangements have also been modified as they were on River Esk and various locomotive in Argentina.

In the case of Antwerp which is part of a National Collection of mueum artefacts I would have thought its owners may also have a few on how it is to be restored.

 

Some points worth considering

1. Most people have not the time nor the inclination to read and understand what Wardle said in his mighty tome on the Red Devil in South Africa. The use of a GPCS system was proven over there but still there was great resistance to use it and constant supervision was necessary with the crews/shed staff was necessary to ensure correct use of the systems. The so called ‘experts’ in UK on preserved railways will be just the same, however the benefits have already been proven and go way beyond the smoke abatement issues.

2. Many locos have been hand fired with a GPCS system successfully and the restoration of a Gas Producer Austerity should be what preservation is all about – preserving what was used in the past. I would however state that the restoration of the stoker is a step too far as we have already heard they where at best problematic especially when the inconsistent sizes/type of coal are taken into account.

3. With regards the front end design – whilst the Austerity will steam OK with its traditional front end design, my experience it is only gives an average performance and even those locos equipped with a Giesel Ejector (a far from ideal device) show much more consistant performance. Resurrecting the Gas Producers Kylpor exhaust system is historically correct and should give improved performance. One postee mentioned the Kylchap arrangement which whilst would work, a proper redesign with a Lempor exhaust will give the best result with the minimum amount of sheet metal work as has been found on many railways.

4. In these days where the Green lobby is king we should grasp the opportunities offered by a GPCS system with increased efficiency, less smoke, less clinker etc etc.

 

I don't know about the implementation of such systems on steam railway locomotives. As I understand it, on e of the big hazards with the generation of producer gas, is the vast quantities of carbon monoxide also generated.

It's fine whilst secondary combustion is in full throng, because the carbon monoxide is all burned up. When you come to a stand and the burning ceases, the fire continues to generate carbon monoxide. It's all-right in small camping stoves but if you get up to anything approaching sufficient size to be a reactor for a farm tractor (about dustbin sized), then it becomes hazardous quantities of carbon monoxide.

Things like oiling up, and changing couplings, presumably become an issue. Your mate presumably needs to know where you are, and more significantly, how to act if you don't come back exactly as/when expected.

Obviously on smaller locomotives this is much less of an issue. Less CO, less confined spaces. If you use roller bearings throughout, then you minimise the chances of getting caught in a confined space.

Carbon Monoxide, is a significant hazard. You can't see it, you can't smell it, it's a poison, and it can suffocate too.

Producer gas is amazing. You can run internal combustion engines on rubber tyres, for example. It makes much more efficient use of almost any organic fuel, than normal combustion. It's not without it's drawbacks.

 

I'm a bit lost on the argument about carbon monoxide, here. Conventional steam locos can produce substantial quantities of CO and other noxious gases when combustion conditions aren't right. We don't have footplate crews keeling over because the gases are confined within the firebox and exit up the chimney, aided by the blower and the buoyancy of the hot gas, which disperses it skywards. Things aren't any different with a gas producer loco.

 

I'd recommend some research on gasification. I'm by no means a subject matter expert, or a combustion chemist.

Gasification is notorious.

I suspect that it's to do with energy density. For example, people have already cited that gasifiers require specifically sized fuel. The smaller the better, in general, I believe. Although the absolute temperature of the fuel is lower than in a conventional system (where the fuel burns directly), I suspect that the energy density of the fire is considerably higher.

If the lumps of coal are the size of small footballs, then the middles are comparatively cool. If they're the size of peas, then the overall energy in the fire, even though the absolute temperature is lower, is potentially higher. In the idle state, the rate of cooling for the fire is more or less unchanged.

Consequently, it takes longer for the fire to go from "working" to "idle". If you just stop the engine, then the demand goes away quite quickly. In the gap, the CO is still being produced, but not consumed. Even though the blast has gone, the fire will still produce CO, at the same rate as when the engine was running flat out. At least that's what I think has to be the case, if the gasifier is to be of any use. Irrespective, it must be the case that smaller fuel particles lead to a greater surface area capable of producing CO. All of this, I assume, is occurring in a boiler which has less overall draw on the fire.

That's quite different from a conventional approach. Feel free to disbelieve, I might even be (god forbid) wrong!

My prime motivation for posting is that I understand gasification to be notorious.

Those who are studying such things for the purposes of implementation will undoubtedly consider these issues if they perform rigorous engineering analysis of their proposals.

The acid test, is that of the crew. If they go dizzy, fall off their engine, exhibit flu like symptoms, feel or be sick, then you'll know for sure.

You're the CEng not me!

 

A curious post this, on reading this you would have thought that the application of gas producer system was a new untried system and its a thing we should approach with caution, however there has been a fair amount of use of it around the world and lots of research to back up what was achieved. In any of the stuff I've read, the problem indicated by 'streuth' has never been mentioned.

Has anyone read if this problem and can point us all in the direction of any papers/ anecdotal evidence of this occurring, or is ’streuth’ just being alarmist?

 

You've twice said that it is notorious but not said what it is notorious for. A fundamental of the successful operation of a steam locomotive boiler is that the off-gases, whether they are CO, CO2, SO2, or whatever, are contained within the firebox tubes and smokebox. Any footplate crew will tell you what happens when they aren't; you get a blowback. At best this will be a sheet of flame issuing out of the firehole and at worst, an out burst of hot gas that suddenly ignites and explodes on contact with air. Avoidance of this is the prime reason for providing a blower. Thus, the hot gases are ejected up the chimney. Being hot, they have great buoyancy and rise up into the atmosphere and become diluted.

Gas producer fireboxes on steam locos aren't something new. They've been around for well over 50 years.

 

my reasoning for asking the question is because it has been raised in descussions at selinge and i dont know that much about the systems and i wanted to find out about how they worked, was the principle suitible for preserved railway use and what the draw backs and plus points were were, after all if Antwerp had the bulk of the gas producer system still fitted, and it was viable to restore her in that form then i would want to get to know as much about the workings as i could , as one day i would probally be driving and firing her , from my experience of firing, i would say the heat exhaustion would to get you before the carbon monoxide would , anyway any gasses would most likily be held back in the box by the blower