# Aster/Accucraft/AML/Roundhouse



## iceclimber (Aug 8, 2010)

Ok, I know that I probably am opening a can of worms here, but for a noob in the live steam hobby, I would like to understand the vast differences between these brands.

I could take a wild guess that quality difference is a big one. I can only afford a certain AML product which is not yet out. I know AML is a part of Accucraft. What should I expect from an AML product? This question stemmed from my questioning of price differences between some second-hand Accucraft products vs. AML products which are priced buy are not currently in production yet.


Please forgive the ignorant noob. 



My limited locomotive experiences are largely in the 0 gauge scale electric. Lionel/Weaver/Williams/Bachman/MTH/(now dis-continued k-line) brands to name a few. Lionel and MTH are the two which most prefer, but there were others like KOHS which specialized in greater detailed engines. I know there are those who love the MTH DCC as opposed to Lionel's TMCC system and that is enough to make those buy from one manufacturer over the other (even if the performance is near equal). I am sure some of those manufacturer prejudices/loyalties apply here as well. 


So, I understand the whole argument of "this is what I know and can expect from this manufacture, so I stick with them". I feel there are good things from both MTH and Lionel and the fact that both can be run on either command system is enough to bridge the gap of differences between the two if one can't make up their mind. Does the same hold true for Live Steam, or is there indeed a vast difference in quality when buying AML or Accucraft?


come on, don't be shy.


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## iceclimber (Aug 8, 2010)

Wow, really?


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## Charles (Jan 2, 2008)

What is the purpose of having "Aster/Accucraft/Roundhouse" in the title? Your post seems to be focused on Accucraft products. AML is a division of products offered by Accucraft.


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## Semper Vaporo (Jan 2, 2008)

No ignorance in your question... just it calls for some subjective comparesons and we are all different subjects.

I have a couple of Aster engines and a friend as 3 or 4 Accucraft engines and I have seen and run a Roundhouse or two. My "bias" is toward American outline engines so I have a bias agaist Roundhouse as most of their offerings are European outline. I also have a bias toward Standard Gauge, so I have a bias against Accucraft since most of what I have seen from them are Narrow Gauge models.

That said, "I think" that Aster engines are just wonderful, but very expensive. Yet, some Accucraft engines can come close to the Aster price range and sure look awfully nice, too!

In general, Aster is what is often called "Museum Quality". This is not to disparage the quality of the other brands, but only to point out the finer detail (not necessarily "more" detail, but more refined parts) of some of the parts on the Aster locomotives. Most people would not notice any difference in the shape and finish of the side rods of any of the manufacturers, but Asters will be slightly more "refined" in looks over either the Accucraft or Roundhouse and you will pay dearly for that slight refinement.

All of them work fine. If you have any problems with any of them you will find the companies stand behind their products and will help you with repair parts (usually free if damaged in transit or, if small detail parts, damaged due to your own ignorance in initial handling of them).

It is said, "Nothing runs like a Roundhouse" and I believe it is true, except, maybe an Accucraft and an Aster... They all run really well.

I think you need to be more concerned with what YOU want it to look like.

Do you like European style engines? Roundhouse or Aster.

Do you want to model a Narrow Gauge engine? All of the three companies make a model or models of a narrow gauge engine.

Do you want strictly an American outline engine? Accucraft or Aster.

Do you want Standard Gauge? Accucraft or Aster.

Do you care about strict fidelity to scale? Aster (and some Accucraft (AMS instead of AML)).

Do you just want Live Steam and a very low price? Accucraft or Roundhouse.

And I am sure multiple people will argue vehemently that my categories above are all wrong and point out models from all three of the companies that meet the opposite of what I listed.

Decide what YOU want and then go look to see what the various companies offer and decide what you can afford and what you can deal with if you cannot afford what you want. (that was my problem... I could not deal with the inaccurate scale, narrow gauge, or non-American outline, so I had to save and save for a long time!).


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## JEFF RUNGE (Jan 2, 2008)

What he said....


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## Two Blocked (Feb 22, 2008)

45mm live steam is not for the faintly heeled. There are checkbook modelers, but they are rare in the operational side of the hobby. A well tuned Mamod on alcohol is as fun, and less work, than a coal fired U232 Hudson. Comparison shopping? Stick to Wally-World and K-Mart and sparkies! One gets what one pays for.


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## rwjenkins (Jan 2, 2008)

So far AML has only done one live steamer, the 0-6-0. I've seen a couple of them in action, and they look good and run well. Being 1:29 scale, the AML stuff is aimed more at the "G scale" crowd rather than the "small scale live steamers", so the lower price point is designed to entice people who may be more used to running plastic sparkies into the wonderful world of live steam, and compete favorably with Aristo's plastic steamers. To keep the prices down, the AML models are mechanically simpler than the 1:32 scale models, with Ruby-style piston valve reversing and fixed valve gear for example, rather than functioning Walschaert's valve gear. They are also offering features that are stock items on some of the more expensive models (water pumps, etc.) as optional add-ons on the AML models to keep the base price down. Quality-wise though, I don't think there's any real difference between the AML models and the rest of the Accucraft offerings. If anything, their simplicity is a plus in that regard. You don't hear a lot of complaints about the more recent Ruby variants, compared to the laundry list of tweaks that need to be made to the cab-forwards to coax the best performance out of them. Each new batch seems to have its own quirks as it comes of the boat from China, but they usually end up being discussed here, so if you have problems with your new K4 you'll have a good support group here, in addition to Accucraft's legendary customer service. 

The Accucraft/Aster/Roundhouse debate is a can of worms that gets opened here pretty frequently, and I think Charles M. (Semper Vaporo) has covered most of the main points for you. Add to that Accucraft (mostly) and Roundhouse (exclusively) produce butane-fired models, while Asters are mostly alcohol-fired (though they have dabbled with gas and coal firing too). Butane firing is easier for the beginner, but the hands-on aspect of alcohol firing has a certain appeal too, as does the prototype authenticity (and smell) of coal firing.


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## tacfoley (Jan 3, 2008)

Just to un-confuse you a little, Roundhouse, an all-British company based in the spiritual home of full-size loco building, Doncaster, build eclectic-styled as well as genuinely replica models of British-outline locomotives in the predominantly British garden railway scale of 16mm to the foot, or 1/19th scale.

They do not make a single European model, although one of the models, 'Billy' has a few details that might, if you squint, remind you somewhat of an Orenstein & Koppel loco.

They DO, on the other paw, make a fine model of the Darjeeling & Himalayan Rwy Class B, and a pretty good version of the Sandy River prarie loco #24. 

Only the basic series of models have fixed gauge 32mm spaced axles - the rest, with the exception of 'Taliesin' and 'Argyll', can run on either 45 or 32mm gauge track.

tac
www.ovgrs.org
Supporter of the Cape Meares Lighthouse Restoration Fund


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## iceclimber (Aug 8, 2010)

For those who offered opinions on the subject, thanks. For those who cleverly laced their snootiness in their reply, just realize that everyone in this world may not be as fortunate to have the resources like you. I am sure you are well aware of that, but I caught a hint of that, and well I guess it is only to be expected. Cheers.


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## iceclimber (Aug 8, 2010)

Thanks Semper.


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## Anthony Duarte (Dec 27, 2007)

Posted By iceclimber on 09 Sep 2010 07:05 AM 
For those who offered opinions on the subject, thanks. For those who cleverly laced their snootiness in their reply, just realize that everyone in this world may not be as fortunate to have the resources like you. I am sure you are well aware of that, but I caught a hint of that, and well I guess it is only to be expected. Cheers.




Iceclimber,
I'm not sure what it is you're expecting from this forum. Not even two hours after you posted, you posted a snotty "wow, really?" seeming insulted that we weren't all jumping to answer your question.
Live steamers are a very small, close-knit group of people, and we're mostly all very opinionated about what we like and don't like about our hobby's offerings.
If you're going to ask such a big question about the distinctions between the three main suppliers, and admit that you have very little experience with live steam, don't be rude in thanking those who've given you their thoughts.
That attitude tends to make people want to keep their experience and knowledge to themselves.

Nonetheless, I hope you find the info you're looking for about the three manufactures you mentioned.


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## rwjenkins (Jan 2, 2008)

Posted By iceclimber on 09 Sep 2010 07:05 AM 
For those who offered opinions on the subject, thanks. For those who cleverly laced their snootiness in their reply, just realize that everyone in this world may not be as fortunate to have the resources like you. I am sure you are well aware of that, but I caught a hint of that, and well I guess it is only to be expected. Cheers.




If you spend any time around a steamup, you'll find we're all a pretty egalitarian bunch really. I've often described myself as a poor man in a rich man's hobby, and had to sell off pretty much my whole collection of HO and N scale (as well as a portable N scale layout) to buy my Accucraft K-27 which is still my pride and joy 5 years later. On the other hand, people seem just as interested to see my Wuhu Porter running as the K-27, even though it's a fraction of the size and price. The "Aster snobbery" that you find on this forum from time to time is actually good-natured ribbing from a bunch of guys who know each other offline. We may have our preferences in terms of things like manual operation vs. R/C, butane vs. alcohol, ready-to-run vs. kit-built vs. kitbashed vs. scratchbuilt, standard gauge vs. narrow gauge, US prototype vs. British or European, true scale vs. whimsical, etc., but trackside we all enjoy seeing the variety of engines that are out there, and the different things we all bring to the hobby. I have never felt looked-down-upon for running my plastic Aristo Mikado next to another's Aster Allegheny or a meticulously scratchbuilt work of art. I've never felt inferior for sitting back and enjoying my butane-fired, radio-controlled K-27 while another steamer dutifully attends to his coal fire. Running live steam is fun, but what is really the best thing about live steam is the wonderful people that you meet at the steamups. I feel really fortunate to be where I am in this hobby, I have a modest collection of locomotives and rolling stock that I got mostly through sheer luck and a bit of sacrifice, but most importantly, I've made some really good friends in the six years I've been involved in the hobby. When the time comes, I'm sure the steamers in your area will be just as eager to welcome the new guy with his new AML K4.


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## Steve S. (Jan 2, 2008)

It is true, no matter if it is the most expensive Aster or a tuned up mamod they are all live steam and a whole lot of fun to run. I can honestly say that I have seen just about all of them run at my track and no matter what the brand they have all run good enough to give their owners fun. Yes, some have run better then others and some have needed a tweak here and there but they all have given their owners enjoyment. Figure out what you can afford and then go from there. No matter if its a Allegheny or a Mamod you will enjoy.

Now as far as bickering, arguing, and thinking that one Loco is better then another.......................... Heck, thats all part of the fun of being here at MLS. I should hope that no one takes it too serious. 
The more famous arguments here at MLS over the past have been *IMHO* :

Best Loco
Best running Loco
Best Loco brand
Best Loco brand for the money

Best steam oil
Best viscosity of oil 

And my all time favorite argument...................................... _WATER, yes................WATER !! _[/b]
Can you use de-ionized water
Will de-ionized water eat your Loco from the inside out
Should you add a little tap water to your distilled water
Can you store Loco with water in it
Why is distilled water so hard to get in the UK

And last........................Why is Japanese water better then all others ??


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## zubi (May 14, 2009)

Hahaha, very funny Steve! Best wishes from Tokyo, Zubi


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## Steve S. (Jan 2, 2008)

Posted By zubi on 09 Sep 2010 08:49 AM 
Hahaha, very funny Steve! Best wishes from Tokyo, Zubi 
_________________________________________________________





Hello zubi. I thought that post might just get you out from hiding. All the best to you too.


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## iceclimber (Aug 8, 2010)

Guess I am not the only one who gets ruffled feathers Anthony.


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## jfrank (Jan 2, 2008)

The Iceclimber is not as newbie as he makes out as he has some 42 posts on here, many on this same subject. My suggestion for you is to first decide what you are interested in, then try and select a locomotive, rolling stock, track and all that related stuff. But, hey that's just me. I like American prototypes and Colorado narrow gauge so that puts me in the Accucraft camp. It also limits what I spend money on. With each different scale and type there is then related rolling stock and such to consider. The costs mount up pretty fast. But some people don't really care about scale or being prototypical so they pull anything with anything. It's really up to you.


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## tacfoley (Jan 3, 2008)

Posted By rwjenkins on 09 Sep 2010 08:29 AM 
Posted By iceclimber on 09 Sep 2010 07:05 AM 
For those who offered opinions on the subject, thanks. For those who cleverly laced their snootiness in their reply, just realize that everyone in this world may not be as fortunate to have the resources like you. I am sure you are well aware of that, but I caught a hint of that, and well I guess it is only to be expected. Cheers.




If you spend any time around a steamup, you'll find we're all a pretty egalitarian bunch really. I've often described myself as a poor man in a rich man's hobby, and had to sell off pretty much my whole collection of HO and N scale (as well as a portable N scale layout) to buy my Accucraft K-27 which is still my pride and joy 5 years later. On the other hand, people seem just as interested to see my Wuhu Porter running as the K-27, even though it's a fraction of the size and price. The "Aster snobbery" that you find on this forum from time to time is actually good-natured ribbing from a bunch of guys who know each other offline. We may have our preferences in terms of things like manual operation vs. R/C, butane vs. alcohol, ready-to-run vs. kit-built vs. kitbashed vs. scratchbuilt, standard gauge vs. narrow gauge, US prototype vs. British or European, true scale vs. whimsical, etc., but trackside we all enjoy seeing the variety of engines that are out there, and the different things we all bring to the hobby. I have never felt looked-down-upon for running my plastic Aristo Mikado next to another's Aster Allegheny or a meticulously scratchbuilt work of art. I've never felt inferior for sitting back and enjoying my butane-fired, radio-controlled K-27 while another steamer dutifully attends to his coal fire. Running live steam is fun, but what is really the best thing about live steam is the wonderful people that you meet at the steamups. I feel really fortunate to be where I am in this hobby, I have a modest collection of locomotives and rolling stock that I got mostly through sheer luck and a bit of sacrifice, but most importantly, I've made some really good friends in the six years I've been involved in the hobby. When the time comes, I'm sure the steamers in your area will be just as eager to welcome the new guy with his new AML K4. 

Yeah. What HE said.

tac
www.ovgrs.org
Supporter of the Cape Meares Lighthouse Restoration Fund


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## iceclimber (Aug 8, 2010)

I do appreciate all the help. I consider myself a n00b still since I have never ever fired up a live steam engine. I apologize as I do wear my heart on my sleeve sometimes.


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## voxnut (Jul 16, 2008)

Iceclimber- 

I too came over from the sparkie world, but my stuff is all prewar Lionel, American Flyer, and Marx tinplate stuff- all "operator grade." So even in the sparkie world my interest is in toy trains rather than model railroading. While I really enjoy my prewar trains, it's very casual- due to space and other interests I only set up the sparkies on a portable holiday layout between Thanksgiving and New Year, but it doesn't diminish my enjoyment of them. 

When I was captivated by live steam three years ago, I brought the same operator grade tinplate sensibility with me and I find that simple visual appeal and affordability are my two governing factors. 

As much as I love going to the National Summer Steam up and gawking at all the impressive high-end steamers, I'm a single dad of a 12 year old son, so I just know in my heart of hearts that a $2K+ live steamer just isn't going to be in the cards for me. I opted for an Accucraft Ruby kit and my son and I assembled it together. Over time it has gotten personalized with a pair of larger 1/2" cylinders (which from what I understand are now stock on the new Rubys) a summerlands chuffer pipe, a couple of cosmetic tweaks, and most recently a Bronson-Tate wood cab kit. It is perfect for our needs and budget and we've been able to do something together and father and son, gain an understanding of live steam (at least as it applies to a basic model locomotive) and tweak it over time while still enjoying it. In short, it has fit what we wanted from the hobby. Customer support from Accucraft has been stellar- a wrong sized jet came with the kit, and later before I bought the summerlands chuffer, I had the original exhaust pipe crack from vibration. I called and within a couple days recieved new parts free of charge. 

I only say this because I'm probably the rare guy on the board who loves live steam as much as the next guy, but can really only fit it into my life on a very casual basis. Perhaps like me, it is possible for you to apply your O gauge tastes over to live steam. If you are into high-rail O gauge stuff, then you probably will want to lean towards Aster or the upper end of the Accucraft line. If you are more of a toy train guy who isn't bugged by things not being to absolute (or sometimes not even close) scale, then you will probbly be pleased with AMS, Roundhouse or the lower end of the Accucraft line. Perhaps the budget is the deciding factor, and that would bring things into the entry level Accucraft, Roundhouse, and AMS line. 

I don't know what part of the country you live in, but if it is possible to attend a steam up, it's probably best to go and see the various steamers in action. As I said, I really enjoy seeing all the different steamers- from the ones that I know are out of reach both financially and committment-wise, to the more humble. It's all fun. But just seeing a lot of different steamers in one spot might help you to zero in on what appeals to you. I do hope in time to get another steamer- the recent Accucraft Forney ($649 list) is appealing to me, or I may in time be able to swing a used Roundhouse Lady Anne or Accucraft 2 cylinder Shay. In the mean time, we'll continue to enjoy the heck out of our cheap little Ruby. 

Happy steaming! 
Dean


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## iceclimber (Aug 8, 2010)

voxnut, 

Thanks. I am in a similar boat as you financially. I have some 0 gauge stuff that my father passed down to me. I am really big into the K4 engines. I have a scale K4 which runs great. Probably will never buy another one(o gauge that is). So, in my situation I am down to either an Aster or the AML live steam K4 coming out down the road frankly because these two are the only ones I know about in small scale live steam). Going to stick with the AML one though for price reasons. 

jfrank, yes, as you have observed, the majority of my posts have to do with the AML K4, as this is what caught my eye in the world of live steam. I knew of the Aster and the sparky versions of the k4 by AML and then I learned of the future release of an AML live steam version of the K4. Affordable (really not, when you think of spending that much on a toy) for me more-so then an Aster K4 second hand or the Aster Berkshire kits still floating around (though that would have been a blast for me to build). 

rwjenkins, you mentioned that some of the lower end live steam such as AMLs have no functioning Walschaert's valve gear. I remember reading on the rundown of the AML K4, that it did have a Walschaert's valve gear. Will this be a "stationary valve gear" in the appearance of the Walschaert's valve gear, or do you think this will be a functioning one? No matter, I really won't mind either way. I do like detail, but at the cost of spending considerably more money, I can live with less. 


When mentioned that 1:29th scale is more for those coming from G scale sparky's (by the way, the AML sparky is not plastic, but brass), i get that the scale is bigger and out of scale with the 1:32nd scale steamers and rolling stock. Why do you think AML went with 1:29th? Is there a specific reason?


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## rwjenkins (Jan 2, 2008)

Posted By iceclimber on 09 Sep 2010 11:00 AM 
I do appreciate all the help. I consider myself a n00b still since I have never ever fired up a live steam engine. I apologize as I do wear my heart on my sleeve sometimes. 
I was the same way before I bought my first engine and attended my first steamup, eager to get started and wanting to learn as much as I could about my new hobby. My first engine was a second-hand Accucraft C-16 that I "accidentally" bought on Ebay, I just put in a lowball bid thinking it would be nice to dream until somebody came along and outbid me, but then nobody did. Not having a layout of my own meant I had to wait a few months before I was finally able to put her on track and let her run, though she did run up a good few scale miles sitting on blocks on the kitchen counter in the meantime! Then when the chance to order the K-27 (what I had really wanted all along but never thought I could afford) came along, I sold that C-16 along with my HO and N stuff to help raise the money. I had to wait a few months after selling the C-16 before the K-27 arrived, and I still recall the anticipation waiting for that big box from Accucraft, and my excitement the day it finally arrived. I'm sure you're feeling the same way about your K4. Trust me, in the end, these things are worth the wait!


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## bertiejo (Aug 11, 2008)

Hi Iceclimber: I have live steamers made by Accucraft, Aster and Roundhouse and all have their strengths and weaknesses. I have formed my own subjective opinions of these brands so here goes: Aster; great quality and highly detailed but expensive and sometimes finicky. High detail on a live steamer is a two edged sword. Live steamers are handled much more (it takes 10-15minutes to get an engine ready for a run and a like amount of time to clean the engine at the end of the day) then an equivalent electric train and they take their knocks in the course of being used (derailments etc). Roundhouse locos dont have quite as much detail but they have enough to satisfy me and they are very robustly made and easy steamers. They are less expensive then an equivalent Aster but more then Accuraft. Accucraft is impressive for the price but isnt quite the equal of the other two. Keep in mind that Accucraft is pretty heavily discounted; if you get on the internet you can compare prices from the various retailers. Accucraft is very accessable in terms of service; Ive called them on a few occasions and was able to reach their service tech who was able to address my problems. I also have an Accucraft UK engine and I got a prompt e-mail response (from Ian Pearse their UK product developer) when I needed some questions answered. While their products are made in China their main US office is in Ca but they have product development offices in the UK and Germany. All three of these companies have improved the quality and running characteristic of their products over the years and there is very little "junk" left out there. The bottom line is that whatever you buy will be good value for the money. Once you decide on an engine you might ask for comments on this forum re its quality, running characteristics etc. bertiejo


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## rwjenkins (Jan 2, 2008)

Posted By iceclimber on 09 Sep 2010 12:02 PM 
rwjenkins, you mentioned that some of the lower end live steam such as AMLs have no functioning Walschaert's valve gear. I remember reading on the rundown of the AML K4, that it did have a Walschaert's valve gear. Will this be a "stationary valve gear" in the appearance of the Walschaert's valve gear, or do you think this will be a functioning one? No matter, I really won't mind either way. I do like detail, but at the cost of spending considerably more money, I can live with less. 


When mentioned that 1:29th scale is more for those coming from G scale sparky's (by the way, the AML sparky is not plastic, but brass), i get that the scale is bigger and out of scale with the 1:32nd scale steamers and rolling stock. Why do you think AML went with 1:29th? Is there a specific reason? 


The valve gear on the AML 0-6-0 has the appearance of Walschaert's gear, but the radius arm is fixed in the "forward" position, so although the eccentric action of the valve gear provides the motion for the valve, reversing is done by switching the valves from inside to outside admission via a piston valve as on a Ruby. I'm guessing the K-4 will be the same way. 

The AML brand was set up specifically to tap into the existing 1:29 market, which is the dominant scale for standard gauge US prototypes in large scale. The scale was developed by Aristo-Craft to be visually compatible with LGB 1:22.5 narrow gauge equipment (a standard gauge boxcar in 1:29 is about the same size as a narrow gauge boxcar in 1:22.5). USA Trains jumped on the bandwagon and the rest is history. Traditionally, 1:29 has been more of a "toy" scale and 1:32 more of a serious modeler's scale, which is why there's such a big difference in price, but lately there has been a trend towards more accurately scaled models in 1:29 (except for the track gauge, which scales out to about 4' 3-1/8"). In a lot of ways it's similar to what seems to he happening these days in 3-rail O scale. Accucraft saw an opportunity to reach out to the 1:29 community, and AML was born.


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## iceclimber (Aug 8, 2010)

I see. I did check the 0-6-0 and while it lists a piston valve and no Walschaert's valve gear, the K4 does mention the Walschaert's valve gear, but no piston valve. Guess we will find out down the road. So how exactly is the engine put in reverse on the live steam w/o the Walschaert's valve gear? In other words, how does the piston valve work compared with the Walschaert's valve? I understand the working of the walschaert's valve ( I think).


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## Semper Vaporo (Jan 2, 2008)

The Walshaerts Valve gear on these types of engines are permanently in the "Forward" position and do impart motion to the valve in the valve chest just like true valve gear. But being permanently in Forward there has to be some other provision to Reverse the engine. 

This is done by a seperate valve hidden between cylinders/valve chests such that the boiler input to the valve chest and the exhaust output from the valve chest can be interchanged such that inside the valve chest is switched from being an "Inside Admission" to "Outside Admission" (or vise versa) to reverse the flow of steam in the engine, which will reverse the motion of the engine. 

If the valve in the valvechest is a piston type valve then Inside Admission is Forward and Outside Admission is Reverse, if it is a "D"-valve then the opposite is true, (unless my addled brain has got that backwards!)

BTW, the hidden valve does not move with the wheels, it is changed by the Reverser Lever, (the Reverser Lever not being used to change the position of the Radius Rod in the Walshaerts Link).


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## rwjenkins (Jan 2, 2008)

Posted By iceclimber on 09 Sep 2010 01:42 PM 
I see. I did check the 0-6-0 and while it lists a piston valve and no Walschaert's valve gear, the K4 does mention the Walschaert's valve gear, but no piston valve. Guess we will find out down the road. So how exactly is the engine put in reverse on the live steam w/o the Walschaert's valve gear? In other words, how does the piston valve work compared with the Walschaert's valve? I understand the working of the walschaert's valve ( I think). 
Imagine a piston-type cylinder valve and valve chest, there is a steam line coming in from the boiler and an exhaust line going out to the stack, and two steam passages going down to the cylinder (one at the front and one at the back). The valve piston is fatter at the ends and narrower in the middle, so in profile it looks like sort of a horizontally-elongated letter *H*. Typically, piston valve engines are what's known as "inside admission", in other words, the steam inlet is between the uprights of the "H" and the exhaust outlet is outside. An "outside admission" setup means the steam inlet is outside of the "H" and the exhaust outlet is between the uprights. In the neutral position, the ports to the front and back of the cylinder are covered by the uprights of the "H", but slide it forward or backward and now one of the ports is exposed to the steam coming in from the boiler, and the other is exposed to the exhaust outlet. Move the piston in the other direction and now the opposite port is getting the steam while the other one is exhausting. The motion of the valves is timed to the wheel revolution by the valve gear. With true Walschaert's or any other type of reversing valve gear, you change direction by reversing the timing of the valves, so an "inside admission" engine will always be "inside admission" whether it's running in forward or reverse, and likewise an "outside admission" engine. 

The Accucraft reversing valve works exactly the same way as a piston-type cylinder valve, except instead of moving back and forth automatically via the valve gear, it is moved manually with the Johnson bar, and instead of the ports in the valve chest going directly to the cylinders, they instead go to the inside/outside ports of the cylinder valve chests. Slide it one way and the steam from the boiler goes to the inside port of the cylinder valve chest while the outside port exhausts, and you're running "inside admission". Slide it the other way, and the steam from the boiler goes to the outside port of the cylinder valve chest while the inside port exhausts, and you're running "outside admission". Basically you're reversing the flow of steam through the entire system, rather than reversing the timing of the cylinder valves.


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## iceclimber (Aug 8, 2010)

Thanks Richard for that description. Yeah, I am excited about the AML k4. I have a few steam engine books I got from the Library so I have some good reading material.


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## jfrank (Jan 2, 2008)

The Accucraft K4 has D Valves(or sometimes called slide valves) so I assume that the Walcherts valve gear works like the rest of their D valve engines which means it also reverses. If you are ordering one at the $2500 price you should get all the options such as water hand pump, axle water pump, adjustable lubricator and goodall valve. If you don't want to spend that much then opt for the goodall valve and axle pump at least. The goodall valve lets you inject water into the boiler while it is under pressure using a simple plastic spray bottle. Once the engine is running the axle pump takes over. Given Accucrafts engines reputation for using up steam oil, I would also recommend the adjustable lubricator. My experience with their water hand pumps suggests that I would just forget that one. Most of mine that came with the engine have been disconnected. I just use the goodall valve in their place. This engine is a good choice since you are already into that scale. Also the engine is capable of taking a 6.5' DIAMETER curve, that is a raduis of less than 4'. So they are building this engine to accomodate the sharper curves prevalent in the 1/29 scale. It looks like it has a blind center driver. Their web site does not give a delivery date. Just call them and ask when they expect it. Their 0-6-0 is also offered lettered for Pennsy once the steam bug has bitten. lol.


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## iceclimber (Aug 8, 2010)

Jfrank, thanks. I have one on pre-order with Mark at silverstatetrains.com 
Mark is a great guy, but most here probably already know that. Cliff from accucraft said they would be on production soon and somewhere around the first of the new year they should be shipping. Who knows though, things could always change. I will be getting all the options. I didn't get the goodall valve, but perhaps I should. Is there a specific reason you didn't like the hand water pump?


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## jfrank (Jan 2, 2008)

Yes, they don't work very well and the hose on both of mine either leaked or blew out. One came from the factory with a split in it.


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## iceclimber (Aug 8, 2010)

That's a bummer to hear. I'll take my chances with the hand water pump. If mine ends up being a dud, I'll hear a voice in my head saying "i told you so", but hopefully since then accucraft/aml will get it right.


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