Steam Loco Question for CNR Fans

Discussion in 'HO Scale Model Trains' started by RobertInOntario, Jul 24, 2008.

  1. RobertInOntario

    RobertInOntario Active Member

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    I have an HO ATSF Pacific loco -- it's a Riverossi/AHM model made in the late-1970s. I'm thinking of converting it to a CNR engine as most of my North American locos are either CNR or CPR.

    Could this ATSF loco be easily converted to (say) a CNR J-7a Pacific? I've attached a pic of my model as well as a historical pic of an actual J-7a. As far as I can tell, it should be fairly easy to do as long as I'm willing to tolerate a few discrepancies.

    I'd just need to add some white lining (as per the old photo) and change the decals, right? I'd also need to add the horizontal black cylinder-shaped object just in front of the smoke stack -- BTW, does anyone know what these cylinder-shaped objects are? :confused: I've always been puzzled about that! :eek:

    Thanks in advance for any suggestions.

    Rob
    GAUGE_ATSF_w__0075.jpg

    GAUGE_CNR_5265b.jpg
  2. MasonJar

    MasonJar It's not rocket surgery

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    If you are willing to live with a few discrepancies, and go for an overall look, then it's possible. doctorwayne has some great material here on adding details.

    The horizontal cylinder is a feedwater heater. It uses the waste heat going up the stack to "pre-heat" fresh water entering the boiler.

    The other major difference between your ATSF loco and many of CNR's (including the one in the picture) is the very Canadian "all weather cab". Note the steps leading up to a door, ot just a space, at the back of the cab.

    You could also modify the pilot (picture shows different handrail config, plus an air tank, as well as boiler tube "plow" versus the steps on the model), number boards, etc.

    If it is a good runner, these details will make it great, but I am not sure that I'd put the time in to appearances if it doesn't run well.

    Consultation with the good doctor and his friend Mr Nutbar is definitely in order! ;) :D


    Andrew
  3. eightyeightfan1

    eightyeightfan1 Now I'm AMP'd

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    Its called a "super heater". Alls I can tell you is that it superheats(don't ask me how...I'm a diesel guy) the steam before being released into the cylinders.
    Maybe a steam guy could help more.
  4. MasonJar

    MasonJar It's not rocket surgery

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    Ed...

    The cylinder on the pilot is a superheater? Or the one on the smokebox?

    Andrew
  5. Triplex

    Triplex Active Member

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    One on the pilot looks like an air tank, on the smokebox is an Elesco feedwater heater.

    Also needs another dome between the existing ones, and raised sides on the tender - looks like 5265 might be an oil burner. Which, incidentally, most Santa Fe steam was, but your model isn't, probably because it's a generic design lettered for Santa Fe.
  6. RobertInOntario

    RobertInOntario Active Member

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    Thanks for your feedback -- this is helpful & I'll see what others say as well. I just bought some 1931-60 CNR decals from George's Trains so I'm off to a start! Cheers, Rob
  7. doctorwayne

    doctorwayne Active Member

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    Rob, you can make your loco into a CNR loco just by re-lettering it, although there'll be a lot of "discrepancies". ;) However, most conversion projects have discrepancies (many fairly accurate brass models do, too!), so you'll have to decide which ones you can live with and which ones you'd like to change. Cal-Scale makes an Elesco feedwater heater with all of the major components, although you'll have to supply your own brass wire for piping. Included with the set is a general piping diagram, which you could adapt to follow CNR practices. Kemtron makes an all-weather cab, in brass or plastic, although it's not the same style as that on this particular CNR loco. Here's a LINK to a loco rebuild thread that shows both the cab and the Elesco system. Correctly-styled CNR pilots are not available (Mister Nutbar seemingly bought the entire supply, with the last one being used on the loco in the link). :p:-D You could modify a Cal-Scale pilot to more closely resemble a CNR type.
    The domes are a different style and in the wrong places, and the layout of the running boards is incorrect, as is most of the piping, the trailing truck, the wheels of the lead truck, and, I would guess, the driver diameter.
    I'm not trying to discourage you, as I love doing such projects, but you have to decide how close you want to come to the prototype and how much time, effort, and money you're willing to put into this. If you can find an older Walthers catalogue, with drawings of all of the PSC (Precision Scale) and Cal-Scale parts, you'll get an idea of what's available for your project and a sense of the cost involved. A full-blown conversion won't be cheap, but, for every such project, there's a point where the results become "good enough". Decide where that point is for you personally, then enjoy doing whatever work you decide is required, and, most importantly, enjoy the results. :-D
    Here's another LINK that shows some of the projects on which I'm working.

    Wayne
  8. RobertInOntario

    RobertInOntario Active Member

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    Thanks, Wayne -- I appreciate your reply. I'm going to print it off and read it over lunch. Also, when I clicked on your link, a dialogue box popped up asking me for a password. When you get a chance, could you please send a password to me via a PM? Thanks so much, Rob
  9. doctorwayne

    doctorwayne Active Member

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    Sorry, Rob, :oops: I had forgotten that the link was to a "Private" Album in my Gallery. I've changed that, so the link should work properly.

    Wayne
  10. doctorwayne

    doctorwayne Active Member

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    Ed, as Triplex notes, the device atop the smokebox is an Elesco feedwater heater. It pre-heats the water before it's admitted to the boiler, using waste heat from the exhaust steam from the cylinders.
    The superheater is located inside the boiler, usually right at the front where it adjoins the smokebox. It consist of a number of tubes through which the steam generated in the boiler is passed. These tubes are surrounded by the hot gases generated in the firebox, as they pass on their way to the smokebox. Because the boiler is under pressure, the steam in the boiler is at a temperature higher than the normal boiling temperature of water; depending on the pressure, about 350-400 degrees F. At this temperature, any drop in pressure (such as when the steam enters the loco's cylinders) will result in some of the steam immediately turning to water. The superheater raises the normal temperature of the steam to about 800 degrees F, which means that the steam can now expand to a greater degree (doing more "work") before any of it changes back to water.
    Locos without superheaters used "saturated" steam, and these can be identified by the "D" valves used on the cylinders, like the loco shown below:
    [​IMG]

    Saturated steam locos used the water in the steam as a partial way of lubricating the loco's valves.
    With no water available for lubrication and the oils and greases of the day unable to withstand the higher steam temperatures, new lubricants needed to be developed before superheaters could come into widespread use. By using a superheater, railroads realised great economies in operating costs,
    as more of the heat from a pound of coal could be utilised, and more energy released from every gallon of water. As a result many slide valve locos were converted to piston valves, either with a new cylinder/valve block casting or with one of the several retrofit kits offered by various manufacturers. After the introduction of superheating, most new locos were built with piston valves, as shown below.
    [​IMG]

    The loco shown above also utilises a front-end throttle (the operating rods extend forward from the cab, alongside the boiler, to a pivoting device on the side of the smokebox). This controls the flow of steam from the superheater to the valves.

    Probably too much of a dissertation on steam for a "diesel guy", :rolleyes: but perhaps useful for steam afficionados. ;):-D

    Wayne
  11. eightyeightfan1

    eightyeightfan1 Now I'm AMP'd

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    Thanks for the info guys.
    Like I said, I'm a diesel guy, and really didn't know how steam works.
    Just that you need fire, and some water....
  12. RobertInOntario

    RobertInOntario Active Member

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    Thanks for this link, Wayne -- it now works. Also thanks for your explanation re the feedwater heater. I'm now having a sober "re-think" about converting my Pacific. You explain the situation well and it could be more work and expense than it's worth. Still thinking about it though!
    Cheers, Rob
  13. RobertInOntario

    RobertInOntario Active Member

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    OK, this is looking like it might be feasible, and done gradually over time. SO I should be able easily get these kits at places like George's Trains, etc.?

    Rob
  14. doctorwayne

    doctorwayne Active Member

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    Pretty well everything you need should be available (eventually). All of my loco projects are currently unfinish-able, while I await parts. Once you determine the changes you wish to make, you can search for the most appropriate parts, which will allow you to get a rough idea of how much your project will cost. I didn't keep track of the cost of parts for "Beeg Boy", but it was well over $100.00. For steam, some manufacturers to check out are: Cal-Scale, Cary, Selley, Bowser, Precision Scale, Grandt Line, and Pia. Older Walthers catalogues have drawings or photos of the parts (I have a 1995 catalogue that does, but sometime after that, the practice was discontinued. You can also write to manufacturers for catalogues, most of which are no longer free. The first four in my list are all in the Bowser catalogue, with all of the others, I think, having their own.
    You should also have the proper tools to do the work, as even the most interesting project quickly becomes tiresome otherwise. For any piping, at the very least you should have a pin vise and the proper-size drill bits. A suitably-sized soldering iron is helpful, but you can get by using ca if the mounting holes are accurately done - glue is not a filler. :p Needle files are useful, and you should have, at least, a flat, a round, and a triangular one in you toolbox. A small vise can be useful, but not essential. Pliers are: needlenose, smooth- and serrated-jaw, all useful for bending "pipe" (incidently, pipe sizes are usually given for the inside diameter - Detail Associates have brass and stainless steel wire in a variety of HO scale inside diameters, with the actual outside diameter of the wire being appropriate for that pipe size). Where possible, don't rely on glue or epoxy to hold a part in place - your loco should be capable of withstanding a reasonable amount of handling. Some detail parts have a mounting pin cast into them - drill a corresponding hole in your loco, then use ca or epoxy to re-enforce the joint. Some parts have no mounting pins: for these, drill a hole in an appropriate spot in the part and use wire to fashion a suitable mounting pin.
    A Dremel tool can be useful, but is not necessary. I use mine quite a bit, though, mostly with a cut-off disk, for shaping parts or removing details. It's also useful for drilling metal parts.
    For carving off cast-on details on your loco, an X-Acto knife is essential. While they have a wide range of blades, I find the #11 and #17 the most useful. Old, otherwise dull #11 blades are useful for cutting the soft DA brass wire - working on a hard surface, such as a sheet of glass, you can easily and accurately "snick" off small diameter pieces. For larger diameters, use a sawing motion, rolling the wire under the blade. For half-hard brass wire (unfortunately, not that easy to find) or music wire, a cut-off disk in a Dremel works best. Cutting pliers will also work, but require the cut to be dressed with a file.
    Other useful tools include: a scale rule, dividers, calipers, alligator clips (for clamping small objects), tweezers, machinist's square, razor saw, mill file, and a set of small screwdrivers.
    Good luck on your project - this type of work, while sometimes frustrating, can be a very satisfying pastime.

    Wayne
  15. RobertInOntario

    RobertInOntario Active Member

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    Thanks, Wayne! I'm thinking I might have time this winter. R
  16. Triplex

    Triplex Active Member

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    Okay, I'll bite. What is the D-valve? I'm not sure what I should be looking at.
  17. doctorwayne

    doctorwayne Active Member

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    Slide valves were used on older locos, usually at pressures of 150 pounds or less. The term "D" valve came about because a cross-section through the valve is similar to the letter "D". Slide valves are "outside admission" valves, meaning that the live steam is admitted at the outside ends of the valve, with the exhaust removed from the centre. When operating pressures were relatively low, this wasn't a problem, but as pressures rose, lubricating and sealing the valve stem became more difficult. The high pressure live steam also acts against the valve itself, pressing it against the bearing seats upon which it slides: the higher the pressure, the greater the friction and wear on the seats and the greater the loss in power. On locos running at higher pressures, the slide valves were "balanced", meaning that part of the upper valve surface was enclosed in order to prevent the steam pressure from acting upon it. Slide valves are recognisable as a squared-off box sitting atop the cylinder casting, as shown below.
    [​IMG]

    And a diagram of a slide valve:
    [​IMG]

    Piston valves are shaped like a spool, with a narrow mid-section and wide ends which fit snugly within the steam chest. Steam enters via the narrow centre area, making most piston valves the inside admission type. Piston valves, by nature of their design, are balanced, as the high pressure steam surrounds the narrow mid-section. The wider ends cover and uncover the the intake and exhaust ports as the valve moves back and forth, with the low pressure exhaust steam on the outside of the valve's body, making lubrication and sealing of the valve stem much easier. Piston valves, generally, appear as a small cylinder sitting atop a larger one, as shown below.
    [​IMG]

    And a diagram of a piston valve:
    [​IMG]

    Like most things, though, there are exceptions, which included a retrofit called the Universal Piston Valve. These converted slide valve locos to piston valves with a bolt-on kit. These didn't look like slide valves, but they didn't really look like piston valves, either. :rolleyes: There were also outside admission piston valves, although they looked pretty much the same as the inside admission type.
    I hope this clarifies things a bit.

    Wayne
  18. RobertInOntario

    RobertInOntario Active Member

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    What I meant to say earlier was that I might use the rest of the summer & fall doing research and acquiring the various pieces I need for this project, and then complete it in the winter when (in theory!) I should have more time. Rob
  19. Triplex

    Triplex Active Member

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    Okay, I learned a while back that square steam chests (that is the correct word?) contained slide valves, but I'd never heard the term D-valve and thought it might be a smaller component.
  20. doctorwayne

    doctorwayne Active Member

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    Yeah, I should have used the more common term "slide valve" - sorry about that. :oops:;) And yes, the valve, either slide- or piston type, is located within the steam chest. :-D

    Wayne