No announcement yet.

GWR Prairie

  • Filter
  • Time
  • Show
Clear All
new posts

  • #31
    It has been a very busy time recently with so many projects needing attention, however I am pleased to report that the Mogul is virtually ready for toolmaking with some final adjustments to the firebox back detailing. We shall be offering many exchangeable parts to create differently detailed locomotives, having the following:-

    1. Tall or short safety valve casings
    2. Original or later B.R. smoke box door with number plate and lamp bracket
    3. With/without cylinder outside steam pipes
    4. Three buffer types including Churchward, Tapered Collett and Straight shank with variations between locomotive and tender
    5. Above or below buffer beam vacuum pipes

    The electrical and mechanical sides have some new features with sprung centre driving wheel for improved traction and a cam pivoted pony truck for cornering stability.
    Andy has designed a new slide in PCB for the decoder and a (speaker if desired) through the smoke box with no soldering and locates in the main PCB for electrical connection.

    Also he has been working on a plug in locomotive to tender tether with no wires to connect and the DCC with sound factory fitted models will include a tender speaker and some other special features


    • #32
      Hello Richard Dapol,
      Firstly, thank you so much for posting these CADs and keeping us 'in the loop'. These models are keenly awaited by myself and doubtless many's great to see it taking shape.
      I'll not make a general critique of the drawings - I'm no authority on the class and there are better qualified people than me to do so. One thing does stand out to even my untutored eye however. The 'swan neck' of the front buffer beam vacuum hose looks exceptionally tall to me, more reminiscent of a Stanier 8F!
      I realise that the size of the swan neck varied between locomotives and that some were fitted with a taller unit. Here's a photo of the preserved 5322 which as it happens has been restored with an accurate replica of the tall swan neck:-

      In the above photo the total length of the swan neck looks to be about twice the depth of the buffer beam. However, in you CAD the swan neck looks MUCH taller! I've had a look at the photo's in David Maidment's "Moguls and Prairies" which detail the class throughout their working lives. None of them match the design in your CAD. In fact the long pattern swan neck seems to have been feature of only some locomotives and one that disappeared altogether after the war.

      Given that this is likely to be a separately fitted component and only appropriate some of the early release models it should be easy to sort this out.

      Other than that the CADs look very nice indeed to me and I'll certainly be 'towards the front of the queue' when it comes to their release! I'll leave it to others more knowledgeable than me to have the definitive verdict on the CADs.
      Thanks again,


      • #33
        GWR 43xx 2-6-0 Mogul progress update.

        Thanks for the update about progress with the 43xx Mogul.

        However as you mention a new "wireless" loco to tender connection, but then go on to say a new slide in PCB to go in through the smokebox door, will be fitted. This implies that the smokebox cum boiler will be full of DCC items rendering the adhesive weight possibilities minimal. As the Mogul is not a large loco and has no sidetanks where adhesive weight can be put, as with the Prairie tank. I fear the model will prove to be incapable of hauling anything like the type of loads it was allocated in real life !!!

        The Mogul's were in daily use often tasked with fairly heafty express passenger trains of a secondary nature. Such as Inter-regional trains to and from the Southern Region on both the Reading to Redhill route for destinations in Kent. But also the Reading - Basingstoke line where they worked the trains through to either Portsmouth Harbour or Bournemouth, with Summer Saturday dated trains. As such these trains could load to as many as 12 coaches !!!

        43xx Haulage potential.
        I am aware of the complexities of providing a user friendly electrical connection between loco and tender. But I would recommend that the DCC items including the possibility for a speaker be put in the tender. So that the whole of the boiler and firebox area is available for adhesive weight aside from the existence of the motor. It must be noted that the smokebox is not a good place for adhesive weight on a 2-6-0 as weight above the pony truck will to some extent, simply reduce the weight over the rear drivers, in a counter-productive manner.

        As my very large exhibition layout 87ft x 23ft, currently under construction for a Railway Museum here in Mora la Nova (Tarragona Region, Spain). Which will be on virtual permanent display when complete. This layout replicates Basingstoke and around a scale 4 miles of this important 4 track mainline. It is therefore fully intended to operate realistic full length (12-13 coach) trains. The layout also models the well known Worting Junction and Battledown flyover which introduces gradients to the layout. The real life 1 in 90 gradient has been eased to 1 in 100 on the model. But still presents a 25ft long climb up to Lichfield tunnel for model trains, as in real life. So I was therefore hoping the new Dapol 43xx Mogul, will be more capable than the old Bachmann version. Which is unfortunately "gutless" partly due to a design limitation in the method Bachmann use to produce steam locomotive driving wheels. Their cast wheels, reduce the amount of tread touching the rails, so reducing haulage capacity. The design also causes vibration which leads to a further reduction in haulage capacity, and significantly increases noise in the model.

        I have already found while testing many current steam locomotive models to ascertain their haulage capacity on the layout. That a steam locomotive model to be capabable of hauling 12 up my 1 in 100 gradient. Requires a minimum weight (excluding any tender) of around 280g. On condition that it is perfectly balanced, and also has machine polished driving wheel treads. The typical lack of traction tyres on British outline models, unfortunately means that many Steam outline models cannot hope to haul anything like their real life counterparts, as supplied. Many however can be modified with the addition of fishing tackle lead shot, to significantly improve their haulage capacity. This does assume of course that available space within the boiler and firebox area is available for such added weight. So for example as Hornby have now moved DCC blanking plates to the tender, the space left inside the boiler is often sufficient, if filled with lead shot, to acheive a more respectible and useful haulage capacity.

        Another minor problem that has become apparant more recently. Is that Hornby's change of production facility around 2013 has necessitated the redesign of a number of steam locomotive chassis'. In a number of cases, this has actually resulted in the newer chassis being lighter, and fitted sometimes with a smaller motor. The GWR Grange class models being typical of the resultant loss in haulage capacity, as indicated in the tables below. It will be noted that "6862 Derwent Grange" bought in 2008 happily hauls 12 coaches up the grade without any modification, with just 261g of weight. Whereas "6868 Penrhos Grange" bought in 2015, would only haul a derisory 7 coaches up the gradient with just 210g as supplied. Adding 65g of lead has only brought haulage up to 10, despite the fact that this makes Penrhos Grange now heavier than Derwent Grange. The older chassis design is therefore not only provided with a bigger heavier motor and chassis but this slightly older design chassis is much better balanced.

        Also of notable interest are the results for the Hornby "Schools" class 4-4-0's, which at around just 276g of weight can haul as much as 14 coaches up the gradient, straight out of the packet. The reason two traction tyres. Dare I suggest that the new Dapol Mogul would benefit from Traction tyres !?

        Up a 25ft Long 1 in 100 real life type Gradient.

        Click image for larger version  Name:	Load haulage tests to July 2018 (01).jpg Views:	1 Size:	1.32 MB ID:	7551

        Click image for larger version  Name:	Load haulage tests to July 2018 (02).jpg Views:	1 Size:	1.49 MB ID:	7552
        Click image for larger version  Name:	Load haulage tests to July 2018 (03).jpg Views:	1 Size:	1.20 MB ID:	7553
        The Duke 71000

        Last edited by The Duke 71000; 21 July 2018, 16:10.


        • #34
          Hello All at Dapol,

          I have spotted something on the new Churchward mogul CADs. This intended to be helpful and constructive rather than carping criticism.

          The problem relates to the width (when seen side-on) of the cylinder block and smokebox saddle.

          I have marked up the relevant part of your drawing and photographs of the prototype to illustrate my point. (see below)

          In your drawings the front face of the cylinders meets the horizontal running plate some distance behind the point where the running plate curves downward (red circle). This makes the front end-cover of the steam chest visible. When you look at the prototype photo however the front face of the cylinder meets the running plate at the point where it begins to curve down - NOT rearwards of it!

          Also, I would query the line of the front face of the smokebox saddle - it should be immediately behind the point where the buffer beam support struts attach to the smokebox. On your drawing there is a gap between the two (yellow circle).

          Finally I believe the rearmost face of the saddle should meet the forward row of circumferential rivets that hold the smokebox to the front of the boiler. (green circle). Again, on you drawing there is a gap between them.

          I have checked in David Maidment's book on the class and can find no photos of 4300s having the cylinder layout shown in the drawing at any stage in their lives.

          In your drawing the cylinders look more like those of a Collett Mogul, where there is a clear gap between the running plate curved drop and the front of the cylinders.

          However, the front and rear faces of the smokebox saddle are still wrong with respect the the buffer beam struts and the circumferential rivets.

          Kind Regards,

          Last edited by Andy GW; 22 July 2018, 18:58.


          • #35
            Just to clarify the points I made above, here are official drawings. I realise Swindon drawings are notoriously inaccurate but they do seem to be correct in this case based on photographic evidence. If you compare the two drawings it seems Swindon moved the position of the curved drop in the running plate forward of the smokebox face when they designed the later Collett Moguls. Your drawing seems to capture the position of the curved drop correctly for a Churchward Mogul. However, both the cylinders and smokebox saddle in your drawing seem to be undersized in the 'x-axis', which is why they don't line up correctly with the bufferbeam struts or the boiler-to-smokebox rivets. It also explains why the steam chest front end-cover is so exposed (it shouldn't be!).

            I hope this is of assistance.

            Last edited by Andy GW; 22 July 2018, 19:11.


            • #36
              Hi Andy, Thank you for your comment regarding the size of the cylinder and steam chest.
              The front was reduced by 0.8mm to help the model negotiate R2 radius curves, but as we wanted to keep the cylinder in its correct central position we reduced the piston end by also 0.8mm. I am now working on this to redesign if possible the front truck to provide more clearance in order to add the extra 1.6mm (both ends) to bring the cylinder overall dimension to 15.00mm (prototype 3'-9").
              Will post a new drawing if this can be accomplished.
              Kind Regards,


              • #37
                Hi Richard,

                Thank you for getting back to me.

                Once again this is intended to be helpful and constructive......

                One approach you might consider is shown below. The photo is of a mass produced OO gauge model of a GWR prototype.

                There are two parts to this method. Firstly, the pony is pivoted at two points, off the centreline of the loco (yellow circles). This causes the effective length of the truck to increase when the loco is cornering, thereby making it less likely to foul the cylinders. Of course it may still foul but to a lesser degree. The second part of the solution is to rebate the inner portion of the front face of the cylinder (red circle).

                The advantage of this approach is that it preserves the dimension of most visible part of the cylinder - the outer face. The rebated inner face is only visible from certain viewing angles and being black and in shadow, is usually imperceptible. Fastidious modellers without sharp curves can glue 'dummy' circular cylinder end covers onto the front of the cylinder if the rebate really bothers them. I've often thought that a clip-on cylinder end cover would make a nice feature in a manufacturer's detailing pack though no-one has done so to date.

                Of course there are very good commercial reasons why you must make compromises in the design of the cylinders to enable these models to negotiate R2 curves. I think most if not all of your customers accept that. Your competitors have certainly been doing likewise for years with no great outcry about it!

                Whichever approach you decide to adopt, I thank you for engaging constructively with the modeller community. Ultimately, we all want the same thing: for this model to be excellent, for it to get great reviews, strong sales and return a profit on your investment.

                Best Wishes,

                Last edited by Andy GW; 24 July 2018, 11:50.


                • #38
                  In the photo exampled in "Andy GW"'s post (previous post above). The method used to operate the pony truck, in what I assume to be an example of another model, does itself have operational issues. As seen this method requires a wider mounting, which not only would make the pony truck on the GW Mogul unrealistic looking. But more importantly requires space that brings it more quickly into contact with the backs of the cylinders. This particular design also has issues when running through pointwork, as there is little or no lateral vertical play in point frog areas. One of the reasons 4 wheel short wheelbase wagon models are the most likely to derail in model pointwork !

                  As Andy mentions, obviously you have to make the model suitable for Radius 2 curves to accomodate as many potentiual customers as possible. Not a problem, because there is a simple solution from what I can see.

                  The simplest solution I would say is to mount the pony truck (because it is a Pony not a Bogie) by using a central screw mounted pivot with a simple narrow metal bar to the axle area, which by its nature will not reach the backs of the cylinders. The cylinders can then be made complete. Then the detail necessary such as guard irons, internal axleboxes, and even the lower half of the real life "Y" shaped arms can be produced in plastic and mounted (clipped possibly) on the lower part of the metal pivot arm. Again so that none of these items impinge upon free lateral travel of the pony truck possibly down to even radius 1. The vertical thickness of the metal pivot arm could also be thickened to hopefully give the pony truck enough weight to deter derailment as required.

                  Food for thought.......

                  The Duke 71000
                  Last edited by The Duke 71000; 25 July 2018, 21:14.


                  • #39
                    Hi Richard & Duke,

                    Thank you for raising regarding double pivoting of the pony truck. I was unaware there was an issue with it, but was told of it yesterday by a very well informed contributor in 'another place'. (OK, RMWeb!)

                    In the interest of balance, I should add that having had a look at the CADs they look very good indeed, with certain areas such as the chimney and firebox being vast improvements on the old Mainline 53xx model from the 80s! All in all it looks very promising.



                    • #40
                      I am very much looking forward to the mogul, as it is a loco which has been in need of a new tooled version for a long time now. The CAD is looking great, but having had some 'interesting' western cab side number plates recently I am interested in how you are planning on doing these? The recent attempts at moulding these have been fairly unsuccessful, and I would much prefer printed numbers which I can then buy plates to go on top of. This way the best representation of the plates can be had, and the identity can be easily changed if wanted.

                      There hasn't yet been any CAD (which I've seen) which include BR smokebox number and shed plates. I find these are very important in making a loco 'look right', and another manufacturer's recent attempt at a Western loco was let down by the smokebox furniture.

                      Many thanks for reading this, and I wish you every luck in the final stages of the model's development!


                      • #41
                        MMCC, Hi, Thanks for your comments. To answer your question take a look at the CAD I published in the 63xx thread <here>. (although the models are being developed together, the threads should have been separated, which is now the case). You'll note the plates are separate parts and there is no moulded 'bead' or plate. Therefore, if you wish can be replaced with those of your choice. This will also be the case with the Prairie.

                        BR versions will of course feature the appropriate smoke box numbers and shed plates. We'll show these in due course.
                        We are now at the final CAD stage of the 2-6-0 mogul locomotive with all corrections completed except for a minor adjustment of the smoke-box saddle/steam chest,

                        Dapol Staff Member


                        • #42
                          Originally posted by Andy Dapol View Post
                          MMCC, Hi, Thanks for your comments. To answer your question take a look at the CAD I published in the 63xx thread <here>. (although the models are being developed together, the threads should have been separated, which is now the case). You'll note the plates are separate parts and there is no moulded 'bead' or plate. Therefore, if you wish can be replaced with those of your choice. This will also be the case with the Prairie.

                          BR versions will of course feature the appropriate smoke box numbers and shed plates. We'll show these in due course.
                          Thanks for the reply and for pointing that out for me! It's good to hear you have it all in hand and I look forward to the model in due course!


                          • #43
                            Dapol 63xx 2-6-0, large layouts, and even larger Diesels.

                            Thanks for the update on the 63xx 2-6-0. I would post my comments on the new 63xx page, but as yet there is NO provision to do this !

                            I must say that I am more concerned with the 63xx mechanism, as detail on the bodyshell is something I can always alter, or add.

                            The problem with the real life 63xx is that these locos were often tasked with hauling trains of up to 12 carriages, particularly on Inter-regional services to and from the Southern Region. This means in model form adhesive weight becomes a very important factor.

                            As I mentioned before you posted the latest pictures. If the boiler is filled with electronics instead of these being put in the tender, I have a nasty feeling the loco will be severely limited in its capacity to haul a realistic load.

                            The motor, worm gear and flywheel appear themselves to be sufficient to haul a 12 car train. But much of the boiler appears to only contain a lightweight electronics board. I would seriously recommend the electronics go in the tender and the boiler be filled with lead, to give the model as much adhesive weight over the driving wheels as possible. Or sadly this model may end up being as gutless as the outdated Bachmann version, which "couldn't pull the skin off a rice pudding".

                            My other concern is the "Clip-Lock" tender coupling. Which certainly sounds better than damage prone tiny wires and microscopic plugs. However what do I do if I want to shorten the coupling to get a real life gap between loco and tender. Is this loco-tender coupling on a flexi-mount to enable it to be realistically close coupled ?

                            Click image for larger version  Name:	Basingstoke layout (02) 6-10-18.jpg Views:	1 Size:	335.9 KB ID:	8055
                            Above: HALF of my part constructed 87ft x 25ft "Basingstoke" layout, with the 4 track Hook station in the foreground, and the 2 track Reading to Basingstoke line to the left. The large 40 track Fiddle Yard starts at the scenic break and beyond the second scenic break in the distance is Oakley station and beyond that Battledown flyover. This layout is obviously large enough to run full 12/13 car trains, so a DAPOL 63xx 2-6-0 will be a useful addition to the fleet to haul Reading - Basingstoke - Bournemouth Inter-regional trains if it can haul 10-12 car loads!
                            Picture taken from 1st Floor level, inside our Museum alongside two large Spanish Broadgauge steam locomotives, which helps to put some scale to the layout.... The other side of the layout including Basingstoke station is still under construction. This was the view at 09.50 Saturday 6-10-18 just before Visitors beagn arriving for our Annual open weekend.

                            YOU WON'T BELIEVE THIS !

                            Click image for larger version  Name:	Young Driver.jpg Views:	1 Size:	455.5 KB ID:	8056
                            Above: Having just had some fun driving my maroon Dapol "Western" up and down my "Basingstoke" layout. 10 year old "Mr Atomic" (in cab window) is just about to take visitors for a little ride on our 900hp 5ft 6in gauge Bo-Bo diesel. Not the first full size diesel he's driven either, as a month back he was in charge of a new 6,000hp Co-Co with the blessing of the Freight Companies Operations Director who accompanied him in the cab. So if you fancy driving something bigger than your Dapol modles, for a small fee you can drive this Beastie called "Yay Yay" . Anything can happen in Spain....

                            The Duke 71000
                            Last edited by The Duke 71000; 6 October 2018, 23:58.


                            • #44
                              It may be a trick of the light, but on the image of the 63xx in the Project Manager's Blog, the front edge of the smokebox door looks to be very sharp, almost square. I refer you to the drawing I gave in post #13, which shows the rounded edge and the profile.

                              Compared to the initial CAD, you have chosen to change the position of the upper washout plugs to be in the 'raised level', as per the preserved 5322. This was rare, and atypical of the class.
                              Last edited by Miss Prism; 14 October 2018, 15:05.


                              • #45
                                Hi Miss P,
                                Thanks for your post. All models will have the washout plugs in the lower position close to the handrail. The CAD for the outside steam pipes shows this, I have attached a scrap view for reference which also shows the separate driving wheel splashers and box covering the air pump. It appears from many photographs that the earlier series of 43xx and 53xx have the washout plugs in the higher position, although pictures of the later 63xx and 73xx do show some in the higher position, but the lower position seems the norm as you rightly say.
                                Tooling is underway and we hope to have an EP during December
                                Kind Regards, Richard