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About jtlan

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  1. L Motor Freezes

    Power functions trains usually require a certain amount of mechanical expertise and fiddling, so the problem may not originate electrically. Would you mind posting pictures of your design so I can assist in debugging? One other thought -- disconnect the motors from the model and try running them. Do they still seize? What if you load them lightly (by grabbing the output shaft)? If so there may be an electrical issue; otherwise, I'm inclined to believe the problem lies in the design of the drivetrain.
  2. Hello CaL, In most photographs of the actual locomotive, the rods are some grey metal, but with the inside of the web painted red. While the Technic half-beams are somewhat rare in red, they do exist, and so I could have used red rods for this locomotive. However, I wanted to make sure the rods were easy to see, particularly while the locomotive is running. The large wheels are official Lego wheels. The small wheels are from Big Ben Bricks. Lego also makes small red wheels, but they are slightly thicker and I would have had to design some parts of the model differently. An extended musing on point 1, above: I think it's important to keep in mind that, as builders, we are building a model of a locomotive, not an actual locomotive. Therefore, it's important to take into account the setting in which your model will be seen. For example, in most cases the model will be seen from slightly above -- design your model knowing what will and won't be seen from that angle. Parts of the model may blend together from a distance -- you might want to choose colors that make those parts stand out. And so on.
  3. [MOC] Umbauwagen 3yg

    Not much of one for painting or discoloring. If the Weinstrasse variant is out of my budget, so be it. The coaches were built after WW2, so a wartime paint scheme would be highly anachronistic. Dark grey is also a very rare color for the window.
  4. [MOC] Umbauwagen 3yg

    Not sure what you mean by "robust", but the linkage features Technic axles reinforcing the sections above the outer axles and three stacked hinges in the joints. It's extremely unlikely to break under normal operating conditions. Thanks! I'm really proud of the mechanism. This model has been over a year in development, if you start counting from the first experiments with the 4+2 arrangement...
  5. [MOC] Umbauwagen 3yg

    No issues whatsoever that I could find. After I worked out the basis I built a test chassis and sent it around a test track as fast as I could. A 9V train motor could pull it at its top speed without derailing. In reverse, the car could be pushed up to very high speeds before coming off the track. Thank you for that information, @RogerSmith. Most of the maintenance cars I found were painted yellow, with the blanked-out windows you mention here. The Deutsche Weinstrasse color scheme is another possibility ... but tan windows are extremely expensive!
  6. [MOC] Umbauwagen 3yg

    Greetings, Train Tech! About a year ago, I posted my Umbauwagen 4yg. Here is the 3-axle variant, the 3yg: The name Umbauwagen means "rebuilt coach" -- these coaches were built after World War 2 by modernizing prewar compartment coaches. More accurately, this is an AB3yg (first/second class) + B3yg (second class) pair -- these cars were nearly always found in close-coupled pairs. A few survive as single units in work trains, painted yellow. The body of the model is essentially constructed the same way as my 4yg model: studs-up construction for the main body (leveraging the train window and the 2x8x2 curved slope), SNOT construction for the doors, the details around the buffer, steps, and corridor bellows. Of course I designed new side frames, and there are a few minor details that are different such as the lights above the end doors of the pair. These cars were painted green in DB service, but as the train window does not come in green I elected to build the 3yg in a different color scheme. I believe that this livery corresponds to 3yg cars used as trailers for the ET 85 electric units -- someone with more knowledge of German railways may be able to shed more light on this. At the time I built the 4yg I also built some test models to research how feasible it would be to build the three-axle variant. However, I ran into difficulties designing the chassis and moved on building the 4-axle variant instead (which had none of these challenges). Earlier this year I circled back and spent some time looking into the problem. The first attempt was to articulate the chassis as 4+2, pivoting the body to reduce the overhang -- a technique I previously used on the tender for my model of the Gr670. However, the Umbauwagen 3yg not only has a long 3-axle wheelbase, but also has a long distance between the outer axles and the buffers: Articulating the chassis as 4+2 would allow the car to negotiate turns, however it would also derail any vehicle attached to it as the buffers swung out widely. Further iteration yielded the general outline of my eventual solution: The center and end axles are connected together with a 6-bar linkage, rather than a rigid frame, allowing the chassis to change shape when traveling through curves. It's important to note that the center axle is actually what actuates the system. As the car enters a curve, the center axle is pushed sideways to follow the curve, which in turn angles the outer axles to follow the curve as well. The track cannot apply rotational forces through a single pair of wheels on one axle, and so a similar design to this one without the center axle would not work. You can see the mechanism here: The outer axles are mounted on 2x2 round bricks riding in a 2-stud-wide channel, allowing them to turn and slide slightly towards the center of the car in turns. I experimented a bit to find the best places for the pivots and a construction that would be light and reliable. In the final model I removed the blue tiles shown in the screenshot, to avoid additional friction and binding in the mechanism. Thanks for following along! As usual, I've uploaded some additional images to a Brickshelf gallery, including some notes on and prototypes of the linkage mechanism. Thanks for reading, and let me know if you have any questions!
  7. Hi CaL, Thank you for the suggestions. However, I'm mostly a purist builder, particularly where electronics are concerned, so I'm happy to use the stock components. I enjoy the constraint of working within the system,and even (particularly?) the challenge of fitting the PF components within a small model. I think a builder can grow a lot by learning and building within constraints, rather than using a third-party solution to "fix" a "problem". Cheers, ~jtlan
  8. Given how small I usually build, this was actually a very comfortable change of pace for me! Still, the shape of the locomotive dictated parts of the layout -- for example, I didn't really have any room to put the battery box in the locomotive itself. Definitely, with this locomotive (and TP56 before it), I thought a lot more about "usability", both in terms of reception as well as battery box accessibility.
  9. Thank you, everyone! I always test the chassis before I get too far along. The drivers display the maximum spacing between axles I'm comfortable with. Thanks, I'm pretty pleased with how the tender came out too. I had to do a partial redesign at one point, as I realized there was no way to get the battery out or to turn it on/off! This isn't the first time I've used that technique. Genealogy of ideas: @Commander Wolf demonstrated it to me after noticing it on @SavaTheAggie's T1. It's wonderfully compact!
  10. Possibly the geometry is off -- are the leading and trailing trucks free to rise and fall a short distance? Failing that, did you quarter the drivers correctly?
  11. Just realized after watching the video -- you've still got the traction tires on the wheels of the Mallard! Remove those, and its performance in curves should improve.
  12. Greetings, Train Tech! Here's a model of the BR24 steam locomotive from Germany, built at my usual 15 inches / stud scale: The BR24 (or "DRG Class 24") were a standard class of German locomotives built in the 1920s and 1930s. As was the case with most standard German designs, plans were drawn up and orders were placed from various manufacturers. They served through World War 2, and continued to serve into the 70s in West Germany, East Germany, and in Poland (as the Oi2 class) Most photos of the locomotives show them fitted with the larger Wagner smoke deflectors (the "elephant ears") -- I've chosen to model the locomotive with the smaller Witte deflectors, which were fitted on a few examples later in their life. I was motivated to build this locomotive for two reasons. First, I wanted a suitable locomotive to go with the Umbauwagen I had built. Secondly, I hadn't seen many new takes on this model since Ben Beneke's version from the early 2000s! There are many builders who have modified Ben's design, often substituting BBB medium wheels for the rare large wheels from the set 7750. However, my typical scale is larger than the scale of Ben's model, and I also wanted to leverage some new parts that have come out since. Like most of my locomotives, this model features Power Functions. A single M-motor beneath the cab powers the drivers at a 5:3 reduction ratio. The locomotive is fairly light but pulls adequately, and there's room in the boiler for additional weight if needed. In a way, this model helps to understand and demonstrate how little weight and torque you can get away with; I see a lot of builders cram extra motors into their locomotive, when the torque can't be transmitted due to a lack of weight. The tender houses the Power Functions receiver and battery box. The 3-axle tender has a rigid frame, with the center axle sliding to negotiate curves (I used a similar geometry on the TP56 locomotive). The body of the tender lifts off for access. The battery box is mounted sideways to better take advantage of the shape of the tender. Coupled together, the locomotive has decent reception from all angles except the front, where the cab blocks the receiver. Incidentally, my model of the 2MT, which exhibited similar reception characteristics, happened to fall off the table during prototyping of this model. About 60% of the 2MT's parts wound up in the BR24, which is actually a pretty good recycling rate! I took the model to Bricks By The Bay 2017, where it spent many hours pulling the Umbauwagen around BayLUG's display. It also won "Best Machine" in the "Scale Models" category: Thanks to anyone who came by to see it, and the rest of the display! Here's the full Brickshelf gallery, along with some Work-In-Progress pictures. I've also brought you some footage of the locomotive in action: Thank you for reading! ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- One final note: Ben was one of the builders who had been active around the time I first started buidling Lego train MOCs -- so in a way, this model is an homage to him. A few of the design techniques used in this model are based on techniques in his models -- the hinges angling the sides of the cab, the 11-plate-diameter boiler, and the way the smoke deflectors are attached. If you're still out there in the hobby, Ben, thank you for inspiring me and a whole generation of builders.
  13. Nice work! It's rare to see engines done at a smaller scale so accurately. Honestly, I prefer the revised boiler -- it more convincingly conveys the shape of the prototype.
  14. Smaller Steam Locomotive Boilers

    You might find the boiler on my Single Fairlie and Lombard Log Hauler of interest:
  15. Thanks! Bonus: I've made instructions and uploaded them to Brickshelf! I welcome any feedback on those, as well.