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GWR Prairie

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  • GWR Prairie

    These look wonderful for OO, but how about shrinking them for N?

  • #2
    A nice idea but with an announcement already in the offing for a mogul, it makes this project less attractive as there are so many shared parts. we also need to revisit the BOB/WC first

    Dapol Staff Member


    • JeremiahBunyan
      JeremiahBunyan commented
      Editing a comment
      Well, that one won't see the light of day anytime soon. My best guess is sometime in 5 years at the least. But I am glad that you'll are still seriously considering the BoB/WC.

  • #3
    I'm very excited for these, I've pre-ordered all of the sound fitted large prairies and moguls from Hattons, could you tell us what will be in the accessory packs for them?


    • #4
      It is difficult to comment on the Prairie, given the low-res nature of your publicity graphic. It is also difficult to judge whether to take seriously what is being currently shown. I assume you are aiming for a post-mid-1950s 41/51xx.

      The Prairie has a major flaw. It's no 2 boiler has been pitched at the same height of the Mogul's no 4 boiler. This is wrong. The Prairie boiler pitch should be 7' 10.75". (The boiler pitch of the Mogul being 8' 2.75".) This error is clearly evident by the gap between the footplate and the underside of the Prairie boiler.

      As a result, all height elevations of significant features (chimney, safety valve, tanks, cab, etc) are wrong. This needs a complete redraw from bottom to top.

      Detail comments:

      - The front handrail is a bit too high.

      - Smokebox darts are too short.

      - Steam pipes are too skinny, although strangely the diameter seems reasonable in the end view elevation.

      - The thick plate on the footplate where the steam pipe goes in needs to be larger.

      - The end elevation profile of the smokebox saddle needs improving.

      - Snifters are missing.

      - Chimney is not fat enough, and should not have a capuchon/deflector. The chimney drawing is: (but leave off the capuchon, of course, not appropriate for the Prairie)

      - Smokebox to footplate stays look too skinny, and it would be nice if they did have obvious 'bends' at their ends.

      - Lubricator cover is in the wrong place, and looks too prominent, and the cover should be radial to the boiler centreline, not sticking out along a horizontal axis. (A reasonable mould release angle should still be possible.)

      - Water balancing pipe is missing. (As are the injectors.)

      - The profile of the top of the windows on the cab front should follow that of the roof.

      - The step on the tank fronts, and those on the bunker rear, should be longer (in side elevation).

      - The base of the safety valve cover is too exaggerated (needs to be as thin as the chimney base). The top feed looks too wide. The sloping sides of the top feed (in end view) are crude, and should be the right mixture of curves. The profile of the cover could be a lot better. Here is the drawing of the low safety valve:

      - Top feed pipes should be a bit thicker.

      - You should check the vertical alignment of the motion plate below the footplate and the motion plate flange above the footplate.

      - The lamp brackets on the front of the footplate are incorrectly positioned.

      - The rear tank top coverplates are in the wrong place. (Although prototypes might vary.)

      - The footplate front handrails are pitched too close, and should be further out toward the footplate edge.

      - Buffer beam steam pipes missing.

      - Buffer stock diameter is too large.

      - Lamp brackets missing from rear of bunker.

      - The handrail on the boiler centreline seems to need spacing off the boiler a bit more.

      - Coupling rod bosses look excessively large.

      - It would be nice to have decent wheel bosses on the carrying wheels.

      - There should be an oil-splash plate behind the front area of the slidebars.

      - Too many bolts on the sides of the smokebox saddle.

      - Lubricators are missing from the top of the tanks (5101/61xx only).

      - The cab rainstrips should be of the 5101 class style and not a 3150 class.

      I look forward to seeing the next version after you've had a look at your "many original GA drawings".


      • #5
        I noticed there were a few things that didn't seem quite right to my eye, the chimney seems like the tapered cast iron type rather the fatter parallel copper capped carried by most of the class. Now the other faults have been pointed out I can't not see them, hope the mistakes get corrected as I would like one or two.


        • #6
          I do aswell as I really do like that Dapol have decided to tackle these two classes, I mainly noticed the missing steam pipe on the Large Prairie CAD, other than that this announcement is very exciting.


          • #7
            Dear Dapol,

            I'm really pleased that Dapol has announced an intention to produce the 5101 and 6100 classes in 4mm scale and I wish the development team the very best in the development of this long overdue model. If you do this model justice I believe it well sell like "hot cakes"!

            As Miss Prism has pointed out however there is much scope for improvement in this initial CAD. Here are a few additional points and clarifications:-

            -The 'Lubricator cover' Miss Prism refers to (point 9) is the sausage shaped blister running across the joint between the front of the boiler and the rear of the smokebox on the Driver's side and is more formally known as the Superheater Lubrication Cover . As Miss Prism said it appears to have been extruded in the horizontal plane rather that radially to the boiler centre line.

            -The chimney shown in your drawing appears to be of the tapered, cast iron type fitted to the 43xx mogul. It is true that some GWR large Prairies were fitted with a tapered cast iron chimney but that doesn't include the 5101 and 6100 classes you are depicting. They were fitted with the parallel sided, copper capped chimney from new until the end of their careers.

            -The locomotive whistles are too far apart and appear to join the cladding sheet on the top of the firebox directly. In fact the whistles attached to a triangular shaped bracket and were fed from behind by two copper 'S' shaped tubes. You seem to have drawn this correctly for the 43xx mogul, but not for the 5101/6100.

            -The detail on the top surface of the side tanks looks particularly weak. You have depicted a firing shovel on the tank top just in front of the Fireman's window. For many people that has bad associations with the product your model is intended to supersede , namely the Airfix 61xx tooling from the 1970s! Can I suggest that you model the 'U' shaped up-stand that is actually an integral part off the locomotive, which the firing shovel is not!

            -Staying with the tank tops, the copper feed pipes conveying water from the injectors to the boiler inlet "clack" valves seem to be represented in half-relief and integral to the side tank moulding. As Miss Prism has said (Point 14) they should be thicker. I am going to suggest that rather than represent them in half relief you represent them as separate components as is the case with the Bachmann Small Prairie against which your model will be compared. Here is a link to a Flickr photo showing these feed pipes as well as the whistle arrangement described earlier. Hopefully you will see that a half relief moulding will not do!


            Finally, can I respectfully suggest that you be more precise in your description of the locomotives you are covering. I see that you have described this project as "GWR 5100 Class (Large Prairie)" on Dapol Digest. The locomotives you are representing are the 5101 class (of 1929) and the 6100 class (of 1931). The term "5100 class" refers to the original 50 Churchward Large Prairies dating from 1903-06 including the prototype, No. 99, from which ALL these locos are descended. Whilst I am sure there would be some who would be delighted if you were to tool up to cover the 5100s as well, I suspect that the additional cost and complexity is rather more than you have intended!

            Respectfully Yours,

            7007 Great Western.


            • Richard Dapol
              Richard Dapol commented
              Editing a comment
              Hi Andy,
              Thank you for your constructive comments, much appreciated. We are waiting for updated drawings which will include many details you mention especially the Chimney and top surfaces which are very important on model locomotives. Our flyer does have the correct description of 5101 Class, which will be corrected on the digest in due course.
              Kind Regards, Richard

          • #8
            On the subject of Prairie tank top detail, I forgot to mention the need for the thin shaped 'cover' between the boiler and tanktop.

            A particularly excellent album of detail Prairie pics (by Brian Daniels) is:


            • #9
              Mogul tender

              - You seem to have put two pivot bars at the front. There should be only one.

              - In side elevation, the standard on the left-hand side should not be vertical, it should be a few degrees off vertical. The internal layout on the upper front left-hand side of a 3500g is complex:

              - Although parallel-body buffers on the tender are not incorrect (for the late period), you might want to consider Churchward taper or Collett taper types to give a better prototype coverage, especially as you have chosen the early pre-1925 underframe style. (The parallel one you have at the moment are too fat anyway, as per the Prairie comment.)

              - The front buffers are too long.

              - Not sure about the depth (vertical) of the steps: see comment on the Mogul body.

              - If you want to incorporate a bit more detail on the water scoop, have a look at:

              - Although there were probably variations on the prototype, the sloping part of the tender coal space is not long enough; it should extend back a further 5mm or so. (Historical photos of tender interiors are nearly non-existent.)

              - Underframe footsteps are not long enough in end elevation.

              - P4 and EM modellers will appreciate 23.5mm clearance between side frames, so please make the frames as thin as you can get away with.

              - The ribs on the sides of the hornguides look too skimpy.

              - I accept you cannot mould the spring hangers separately, but please give the springs adequate lateral depth. (This is usually one of the worst failings of many current RTR tenders.) Get the spring shackles outside the front of the frame if you can:


              • #10
                Mogul body

                - Driving wheel vertical clearance in splashers: most modellers would I think prefer you to adopt a course of action based on keeping the footplate at the correct height, keeping the splasher radius as close to prototype as reasonable, but slightly reducing the driving wheel diameter. 22mm wheels with RP25 flanges should be fine. Keep the splasher top and side thickness as thin as you can please.

                - I'm pleased you have not chosen the uncommon washout plug positions on the preserved 5322.

                - Your graphic gives the impression of a abrupt transition between the lower part of the firebox side and the bottom part of the firebox side. It should be a smooth and subtle transition. (Oxford got this very wrong on their DG.)

                - You seem to have chosen a later and longer 73xx steam pipe length. For most of your locos, the steam pipe should be a lot shorter than you have shown, i.e. a lot closer to the saddle. There is a tricky tapered-thickness flange on the smokebox where the steam pipe enters.

                - There is an incorrect misalignment of the lower and upper parts of the motionplate.

                - Cab steps: on all Moguls, there was an excellent horizontal correlation of step heights with the step heights of their 3500g tenders. You currently have a significant mismatch.

                - Right-hand side middle splasher: for your locos (after 5380, with the smaller flanged motion plate), I think you will want the later style where the reversing rod is outside of the splasher perimeter (rather than the early style, as per 5322 etc, where the middle splasher extends outwards and the reversing rod goes down a recess in the top of the splasher). I'm not sure of my ground here: maybe others can confirm this.

                - Don't forget the step at the bottom of the smokebox front.

                - Your tapered chimney would benefit from a little bit more taper.

                - Handrail plan view: avoid the abrupt kinks, the handrail went smoothly from first boiler band to the firebox side.

                - The Prairie comments on smokebox dart length, steam pipe plate on footplate size, front boiler stays, and front lamp bracket positioning, all apply to the Mogul.

                - Be brave and make the boiler bands scale thickness. Go on, I dare you...

                Great set of detailed pics, concentrating on 5322:


                • Richard Dapol
                  Richard Dapol commented
                  Editing a comment
                  Hi Pm
                  Thank you for your extensive comments, details and picture galleries, most of which are already being prepared in our next pass of the various drawings. I do have a comprehensive series of pictures I took of 4144 at Didcot many years ago. Regarding the Mogul, if you have a chance to view my Lionheart 7mm. 43xx series of models which will give you some idea of what we intend to reproduce in 4mm. scale.
                  Thank you again for your constructive comments. Kind Regards, Richard

              • #11
                Hello Again All,

                The following comments are again intended to be constructive and helpful.

                In answer to Miss Prism's question concerning the Driver's side splasher, the following is from David Maidment's "Great Western Moguls and Prairies". "From the first, the 4300s had their right hand centre driving splasher extended forward to clear the reversing rod.From 5390 onwards, this was modified to allow the reversing rod to be placed above and clear of the standard sized splasher".

                Dapol's product announcement page of 15th December says in its opening sentence that the scope of this project is restricted to 5390-7321.

                There will be those who will be disappointed that earlier and later variants are not being covered. However, I think they are wise to say at the outset what the scope of this project is to be, whatever that scope may be. The alternative would be to leave it 'open ended' as simply "43xx" which could raise expectations that many or all of the numerous revisions to this class will be covered. As I'm sure Dapol are aware, a competitor recently released a model of a locomotive dating from the late Victorian era which saw many changes over a very long service life. By NOT defining the scope of their project at the outset they raised hopes that tooling would be made to cover detail changes going back to the early 20th Century. The model itself, when it emerged, was a not-at-all-bad representation of the prototype in late condition. However, early configurations were not covered and this led to considerable misunderstanding and rancour with some potential customers.

                On the subject of the scope of this project, I've noticed that one of the prototype locos chosen, 7324 (4S-043-004), is one of the later "Collett" moguls which featured windows in the cab side and is therefore not within scope. Is this an error or a 'Freudian slip' of future intentions? ;-)

                Respectfully yours,

                7007 Great Western


                • Richard Dapol
                  Richard Dapol commented
                  Editing a comment
                  Hi Andy,
                  Sorry for the late reply, I am currently out of the country.
                  We chose the later batch of locomotives as they covered most eras including the more prolific in later B.R. days. We could at a later date make the earlier models, however this will necessitate making new footplate and cab mouldings plus motion bracket support and other details such as original Churchward buffers, copper caped chimney cab port hole windows, etc. Yes model number 7324 is a typo error should be 6324.
                  Thanks again for your interest, Kind Regards, Richard

              • #12
                Thanks, Richard. A couple of minor extras:

                Front elevation on both Prairie and Mogul: the minor radius of the handrail (over the smokebox) at each side should be larger.

                Just checked a few old Didcot measurements: Mogul vacuum pipe diameter over braid is 2 7/8", and front boiler stay rod diameter is 60mm.


                • #13
                  Richard - no doubt you've got this already, but here's a 4'9" diameter smokebox front (from a 94xx), which is Prairie size iirc, showing the characteristic radii of the Churchward/Collett smokebox ring.

                  Click image for larger version

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                  • Richard Dapol
                    Richard Dapol commented
                    Editing a comment
                    Hi Pm,
                    Thanks for your notes and details, much appreciated. The Mogul drawings only require some minor corrections before tooling will start, then I can concentrate on making the changes to the prairie.
                    Kind Regards, Richard

                • #14
                  In my comments on the Mogul tender, I may have been wrong about the 'only one pivot bar at the front'. There is possibly/probably also a short one on the right-hand side:

                  Pictures of the front of 3500g units are rare!


                  • #15
                    Hi Pm,
                    Thanks for the picture of the tender. I am going over the necessary changes to the CAD which I plan to finish next week, and as soon as these have been done I will post the latest CAD here
                    Kind Regards, Richard