steam loco question

raysaron Jun 12, 2002

  1. raysaron

    raysaron TrainBoard Supporter

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    at a railroad museum, there was a large scale model of a steam locomotive: two sets of drive wheels with the cylinders between the sets of drive wheels (cylinders were back-to-back)

    ooOOO cc OOOoo--tender

    c=cylinder

    Were there steam locos with this arrangement?
     
  2. Bill Kamery

    Bill Kamery TrainBoard Member

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    Sounds like the UP Challenger (4-6-6-4)? I think a real one is coming to Wisconsin soon!
     
  3. RidgeRunner

    RidgeRunner TrainBoard Member

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    Nope, Challengers didn't have the cylinders back to back, did they?
     
  4. Kevin

    Kevin E-Mail Bounces

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    yes, the engines existed, but they were never operated in the US. Reminds me of something around South Africa, but may be wrong.
     
  5. watash

    watash Passed away March 7, 2010 TrainBoard Supporter In Memoriam

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    The Garrett articulated was made like this. The boiler and cab was suspended between the two separate engine driver frames.

    The advantage of this design was to allow negotiating tight curves, and due to the pivot points, the weight of the boiler was carried inboard toward the center of a curve, which made it very stable.

    American articulateds were made with the rear driver frame mounted solid to the boiler. Only the front set of drivers could swivel which served the purpose, but did cause a good deal of boiler weight to be carried out over the outside of a curved track. Full sized articulated American engines could negotiate a maximum curve of 20 degrees. Narrow gauge articulated engines could go around even tighter curses, but only at slow speed.

    Because of the abundance of tooling already in use for HO model track, made to an 18" radius, the manufacturers chose to make all their model articulated engine models to swivel both sets of drivers to enable them to go around this existing curved track. Thus the totally unrealistic appearence of the cab swinging way out into the field which of course would make an impossible situation for the crew.

    We wrote letters, made phone calls, screamed, spit, and generally raised .............HE(double golf clubs)..., until the manufacturers finally started making larger radiused track.

    Bowser and Varney were the only ones who had "Scale" articulated engine models, but the best they would do is a very tight 36" radius curve. Because their boilers were brass and lead, they would tip over when entering an 18" radius when we modified them to swing that far.

    So we had to buy Tru-Scale wood roadbed and hand lay our rails to suit the engine. Tru-Scale made curved roadbed up to 60" radius.
     
  6. 7600EM_1

    7600EM_1 Permanently dispatched

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    Watash,
    I hate to call a bluff on you, but I am! The newer Bowser Articulateds, with die cast Zamak boilers will run on 18 inch radius track! All of the ones I built so far will without any trouble... As for the older ones, I have assembled a few but the problem is, that I never tried to run them on any curved track! I had test ran them, but on straight track only... a 8 to a 10 foot board straight with one rail on it and it ran fine on that so. Now I don't use that anymore but I use my own layout (being then I didn't have a layout) so I took that test track apart to use the rail on it to use on my layout but these Bowsers I'm building run really well without any speed restrictions on curves of 18 inch radius... I guess Bowser had redesigned their first design to now negotiate sharper curves.
     
  7. watash

    watash Passed away March 7, 2010 TrainBoard Supporter In Memoriam

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    I am told the new pot metal boilers are not as heavy as the old original brass sand cast boilers. There is a difference. Bowser had to make their rear driver set to swivel inorder to be in competition to the other manufacturers. Today's layouts are smaller than in the olden days so proper radius curves are not an option to most of the buying public.
     
  8. 7600EM_1

    7600EM_1 Permanently dispatched

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    Watash,
    Yes their is a difference in weight the brass sand cast boilers were heavier then the new or newer Zamak boilers, most certainly, but no, the rear set is just like the old brass sand castings. The rear set of drivers mount solid to the cast Zamak boiler just as the Brass sand cast boilers did! I don't think they did awhole lot of retooling on the boilers besides the fact of different materials so... But they may have made the front set of engines swivel more the the older ones did. Being on the Bowser Challenger, I can run it on 18 inch radius curve with no trouble, besides the unrealistic overhang... Besides that It runs well on 18 inch radius curve track.

    The old Brass Bowser castings to the new or newer Zamak cast boilers are made just as the real articulateds were, the rear set of engines are the main boiler support, while the front set of engines done all the articulating.
     
  9. porkypine52

    porkypine52 TrainBoard Member

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    Ray where was this museum? Did it have a website? I don't think that you saw an articulated engine like the kind that everybody is talking about. You may have seen a "one of a kind" logging engine or such. There were some really odd looking engines around. I am sure that WATASH can atest to this!
    I guess I don't get the idea of running a Mallet on a small radius curve. The engine really looks stupid on a small (18" in HO) curve. If you a going to run big power at least make sure that your layout is built to handle the size engines you want to run. A month or two ago, in the MODEL RAILROAD NEWS, some guy was crying that his BACHMANN 2-10-0 would not run thru an ATLAS #4 (really 4 1/2 ) SNAP SWITCH. I say "get real" a 2-10-0 has no business around anyplace with #4 switches. This is the exact reason that I don't have ANY mainline #4 switches on my N-Scale layout. The only #4 switches are in the coal mine branches, and several leads are restricted to 4 axle diesel power or short wheelbase steam.

    Let's Go Run Trains!
    MARK
     
  10. Cid

    Cid New Member

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  11. raysaron

    raysaron TrainBoard Supporter

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    Cid:

    These photos look similar to what I rememeber. I wish that I had looked
    more closely. I'm not even sure that
    it wasn't a tank loco (no tender) now
    that I try to remember.

    The model is high on the east wall of
    the National RR Museum in Green Bay,
    WI gift shop. Since it was up so high
    on the wall, what I recall most clearly
    is the running gear with the back-to-back
    cylinders.

    Thanks for the info. When I'm there again,
    I'll look more closely.

    Ray
     
  12. Mike Sheridan

    Mike Sheridan TrainBoard Member

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    Just a thought .. could the museum staff have put it on the shelf with the front wheels the wrong way round? :rolleyes: (Don't laugh. I am actually being serious here guys [​IMG] )
     
  13. pjb

    pjb E-Mail Bounces

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    The CanPacs mallets had centermount cylinders w/ hp & lp engines operating in differering directions. Many of the various Fairlies,Meyers, and locos combining woo woo woo-Lindner dual engines (which could employ features from a variety of other designs also) had the high pressure and low pressure cylinder sets mounted in board. That said, I can't recall any with 4-6-6-4 setups. This is because none of them were designed for high speed (45 m.p.h.+) running, but rather to maximize T.E. on twisting heavy grades for the most part. The K-L axles more or less obviated the need for pilot wheels, and over half of all the locos in these categories (300+) had them. Many of the Myers variants were rack locos , or combinations of rack and gravity adhesion so they had no use for four wheeled pilot trucks.
    Basically it comes down to Garratt types. DJH, that has the largest line of model steam locomotive kits, makes several. Use Google, or similar comprehensive search engine, to find DJH's website and look at their samples from SAR,Australia, and elsewhere. Brittania Models, in Vancouver, is their North American wholesaler/agent and they also are on the web.
    Good-Luck, Peter
     
  14. Cid

    Cid New Member

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    Hi Ray
    At last a response, if not the answer!!
    QUOTE:
    "Subj: Back-to-Back Cylinder Model.
    Date: 6/24/2002 2:33:06 PM Central Daylight Time
    From: cschuetz@nationalrrmuseum.org (Charles Schuetz)
    To: Cidchase@aol.com

    Dear Mr. Chase:

    Thank you for your recent request for information regarding our 4-6-6-4 steam locomotive model. Indeed, it does have back-to-back cylinders, which is peculiar; nevertheless, I must confess I haven't a clue whether it was modeled after a specific locomotive or just the work of a creative imagination. I will, however, ask my fellow staff members about this model. As for photographs, I have not come across any within our photograph database. I will write again when I have further information.

    Sincerely,

    Charles E. Schuetz
    Curator

    National Railroad Museum
    2285 South Broadway
    Green Bay, Wisconsin 54304-4832

    (920) 437-7623, Ext. 14 Telephone
    (920) 437-1291 Fax"

    cschuetz@nationalrrmuseum.org

    This is definitely progress!!
    Hopefully, more to come,
    from Olive Branch
    Cid :D :D :D
     
  15. raysaron

    raysaron TrainBoard Supporter

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    Cid:

    Thanks for the info.

    I guess I thought that they would not have
    info on minor items in their collection or I
    would have contacted them myself.

    (The trip there was a rented van with 13 of
    us and everyone said it was a worthwhile
    trip.)

    Ray
     
  16. pjb

    pjb E-Mail Bounces

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    There is another possibility, which I didn't consider since the subject was being discussed in terms of articulated locos. To whit, duplex steam locomotives which are multi-engined locos with fixed wheel bases. The PennRoad had 4-4-6-4s,4-6-4-4s,4-4-4-4s, 6-4-4-6s and possibly other wheel arrangements. The B&O's "Emerson" was also a duplex, and probably others were made around the world. I know of no specific duplex with the wheel arrangemant described , but that may just reflect my incomplete knowledge.
    Good-Luck, Pjb
     
  17. 7600EM_1

    7600EM_1 Permanently dispatched

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    The B&O's duplex "Emerson" was a reversed duplex in design! The front set of engines cylinders were in the normal location. However the rear set of cylinders was not. They were behind the drive wheels under or near the firebox! kinda like a Cab Forwards set of cylinders... This lead to the thought of being dual powered still, and having an even shorter driver wheel base then any normal duplex. of the same size and wheel configuration.

    As for the Pennsy duplexes, they were made just like a atriculated only they didn't articulate!

    [ 29 June 2002, 05:03: Message edited by: 7600EM_1 ]
     
  18. pjb

    pjb E-Mail Bounces

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    For what it is worth there were 4-6+6-4 Garratts operated in Brazil and Colombia, built by both Beyer-Peacock and others. A far more common variant found around the world, to which some of these were converted for better running with less track damage is the 4-6+2-6-4 form. There were also double pacific passenger Garratts.

    I'm not sure that I understand the comment viz. Pennsy Duplexes. By definition they were not articulateds if they are duplex locomotives. While one can incorporate differing elements of articulation in a single locomotive. Notably.O&K''s more than a thousand locomotives having woo woo woo-Lindner axles (which are split w/differential gearing allowing differing engine side thrusts to be dealt with independently in order to negotiate tight curvature , rough track,etc.-more efficiently than any solid axled engine type) with Meyer (AKs), Fairlie, or Mallet forms of engine unit mounting in a locomotive.
    However, if it isn't articulated in some way , regardless of the number of engines it has, a rigid framed locomotive is not an articulated.
    Technically swivelling trucks equipped with booster engines( Bethlehem called them auxiliary locomotives) make any locomotive equipped with some form of such a device an articulated locomotive. Which also makes the MoPac 2-8-8-2 mallet equipped with booster engines on both tender trucks just about the only four engined steam locomotive to operate in North America.
    Good-Luck, PJB
     
  19. 7600EM_1

    7600EM_1 Permanently dispatched

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    pjb,
    The relating identity to a Pennsy Duplex is very simular to a Articulated. Look at a Articulated, and then a Pennsy Duplex. They were identical in looks. Only the Articulated had the front set of engines to swivel. Where the Pennsy Duplexes were rigid mounted (non swiveling) Thats the only difference. Besides the fact of wheel arrangements. The cylinders on both loco's were in the same location as for the trailing or pilot trucks... This is what I was saying in a previous post.

    All that said I was commenting on the difference of the B&O's "Emerson" Duplex compared to a Articulated or a Pennsy style Duplex. Being that the B&O "Emerson" was in fact different compared with a set of cylinders in the normal front location and on the rear set the cylinders was behind the drivers and ran backwards from the front set... It was like having a normal rigid frame loco on the front and a set of engines from a Cab Forwards in the back. All mounted rigid to the boiler instead of being articulated.

    As the Pennsy Duplexes, They were like having 2 normal rigid frame loco's mounted under one boiler rigidly instead of articulated... See? Its kinda hard to explain without having some reference to the different types of loco's to look at....
     
  20. watash

    watash Passed away March 7, 2010 TrainBoard Supporter In Memoriam

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    Raysaron, this must be the engine you saw! I have a sneeky friend in Wisconsin that sent me this photo. All I know is it must be an outshop photo of a CP engine, but it does have the cylinders mounted between both sets of drivers as you remembered!

    [​IMG]
     

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