Hod Carrier

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About Hod Carrier


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    Good ol' U of K

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  1. Correct. The reason why the cars were "bunching" was because there were too many pivots between the fixed point which meant that the couplers would "fold up" when the cars are pushed. You are right to say that a rigid mounting to the chassis would prevent this from happening. This is the real problem. The axles need to be steered because they cannot self-steer themselves, and the best (only...?) way to do this is through the couplers. Without this there would be nothing to align the axles with the track whatsoever. I did come up with a solution to the "bunching" issue, which was to add a small elastic band to the coupler magnet itself to keep it centred. This was sufficient to keep the magnets correctly aligned when the train was pushed which also kept the wheels correctly aligned with the track. I'm not entirely sure that a re-profiled LEGO wheel would have sufficient effect to ever make it fully compatible with LEGO curves and make them work in the same way as real train wheels, but it might possible if the curve radius is generous enough. I think you've asked a very valid question. Very few model railway systems ever truly mimic the operations of real railways in terms of vehicle dynamics, but the LEGO system is almost comically unsuited. No real railway has curves as freakishly tight as the LEGO system and so no vehicle designer ever has to consider how to make their vehicles traverse them. I guess the answer for us depends on personal preferences, and this is often a factor that gets touched upon whenever the question of scale comes up. Do you design your cars to scale with the track with dynamic characteristics to suit or do you look at ways of modifying either the track or the cars to work together in a more harmonious way? There is no right or wrong answer to this question. Some people like playing with the scale to make shortened LEGO-friendly caricatures of real trains while others like to push the boundaries of what is possible with LEGO by creating correctly scaled behemoths and then engineering them to work on LEGO track geometry. Personally I don't think we need to be limited by LEGO track geometry. I believe that there are ways of engineering solutions to most track-related problems, and this investigation was one example of this approach. There's no reason why a two-axle vehicle needs to use fixed axles with all the limitations this brings when there are alternative methods we can use to achieve compatibility between the train and the track. LEGO is traditionally seen as merely a toy and not worthy of serious consideration amongst modellers because of it's perceived crudeness, a perception that TLG seems unwilling to refute. However, this does not mean it is impossible to create some truly stupendous creations that, at first glance, really shouldn't work but somehow do. I like stuff to scale correctly if at all possible and try to get as close to realism as I can. This is one aspect of this hobby that I find incredibly attractive. The chance to show someone something and have them say "Is that really LEGO...??" and to undermine their preconceptions is priceless. But those are just my thoughts. As I said before, there are no right or wrong answers to this question and it's up to everyone to make their own judgements. Often it's simply a question of space that dictates the size of everything.
  2. Let’s talk about standard train wheels...

    I agree. Weight is simply magnifying the problem you already have, which is that the wheels are binding against the rails creating unwanted friction. At @12 studs between each axle your car is quite long to be using fixed axles like this. If you have too many cars of this type in a train or your loco is not sufficiently powerful to overcome the friction you will find that it starts to become a problem. A single lightweight car like the cattle car in set 60051 would be fine, but you're talking about an entire train. Each car you add to the train multiplies the amount of friction experienced. If you don't want to use bogies you will need to explore methods of axle articulation, such as was used in the thread I linked to yesterday. That last photo shouldn't be anything to worry about. It's simply the swing due to the length of the overhang at the end of each car. Yes, each car is trying to pull the other slightly to the side, but it's not adding too much additional friction and the articulation on the magnets is sufficient to deal with this. If you set up almost any train onto a bend like this you will see a similar twisting of the coupling magnets.
  3. @bradaz11 Real trains work very differently from LEGO ones, and this is the main reason why vehicle dynamics have to be considered differently. Real train axles naturally self-steer because of the cross-sectional profiles of the train wheels and track. The diameter of the wheel tread is largest next to the flange and reduces slightly as you measure away from it. As the axle enters a bend the wheels move laterally towards the outside of the bend. As a consequence, the diameter of the outer wheel where it is in contact with the rail is larger than the diameter of the inner wheel meaning that it will travel further per revolution which causes the axle to follow a curved rather than a straight path. It is this difference in wheel tread diameter that causes the axle to follow the bend, not the flange itself as is commonly believed. You can push a rail axle down a length of track and it will follow the bends happily without any intervention. Rail vehicles take advantage of this by allowing each axle a certain degree of movement within the suspension to permit each axle to steer itself relative to the position of the vehicle body, allowing the vehicle to take bends without creating unnecessary wear to rails or wheels due to excessive friction. LEGO rail wheels and track are far cruder meaning that a LEGO axle will not naturally self-steer in the way that a real axle would. Believe me, it would be far, far easier if LEGO axles did behave this way because you could then be sure that they axles will follow the path of the tracks. But because they don't, any steering effect you get can only be achieved by applying some force to the axle assemblies directly. In the case of the vehicles that I and others were testing, this force was applied through the coupling to the neighbouring vehicle. Free steering axles that had no steering force applied would not follow the course of the track, refused to self-centre (even when at the very rear of the train) and were frequently the cause of derailments. I did not experience any problems with the buffers steering the axles off because I made sure there was sufficient articulation to ensure that the buffers never made contact with each other. This might be a problem if they were rigidly mounted to the vehicle itself, but mine were attached to the axle assemblies which prevented any interference. Certainly one solution to this problem would be simply to use larger radius curves, but not everyone has the luxury of space to use them and many have to make do with LEGO's standard curves. As a result, focusing on the vehicle rather than the track makes the solution accessible to more people. I'm sure that those people or clubs lucky enough to have the space for large radius curves will have looked at this and decided it's not required for them, and that's fine. But for the majority of us it opens the possibility for running scale length vehicles on the standard track without the excessive friction and derailment issues previously experienced by trying to run long-wheelbase vehicles with rigidly mounted axles. To answer your question about real rail vehicles, there are indeed limits to how large a two-axle vehicle can be. Partly this is down to vehicle dynamics but partly it is due to axle loads. The model VGA wagons that I built on the back of this testing are representations of the largest two-axle vehicle to run on the UK rail network. There may be larger vehicles of this configuration elsewhere in the world, but anything larger than this in the UK would require bogies. The trend in rail freight has moved away from trains formed of large numbers of small wagons towards smaller numbers of large wagons. This gives greater efficiency of operation and permits larger loads to be conveyed in trains of equivalent lengths by reducing wasted space thereby increasing the load density. I hope this answers your questions, but if you'd like to ask more I will be happy to answer.
  4. Let’s talk about standard train wheels...

    It is possible to go longer, even with a larger overhang at the car ends, if you allow the axles to articulate. A few of us did some investigations about just this sort of problem earlier this year (click). However, looking at your models I would estimate that the problem is not to length of the wheelbase (the distance between the axles) but, as @sed6 suggests, the buffers are interfering with the way in which each car moves relative to it's neighbour.
  5. MOCer's will you buy the new train sets?

    I think we’re kidding ourselves if we believe that we’re a large sector that TLG needs to take notice of. Trains is probably the least well supported theme they produce. It’s perhaps not the most scientific measure, but just look at the relative size of this forum compared to the others on Eurobricks. So why should TLG feel any great motivation to pander to what we want (especially when we’re so divided amongst ourselves with respect to what we want)? I’ve said elsewhere that I’m happy as long as TLG produce train parts, and that’s what they are doing. Buying a whole set just to extract the PF components seems like overkill to me, but I respect those who are intending to do this. What I don’t see is any reason why I should buy sets I don’t want simply to prove my loyalty and support to the theme.
  6. MOC - Garden Toy Train - 12-wide

    That’s lucky. I guess your build doesn’t include any of the parts where LDD fails to agree completely with Bricklink. As well as modifying your build to suit Bricklink, be aware that you can also look for alternative parts within the Bricklink catalogue. There are often minor variations in design, but LDD doesn’t differentiate between different versions of the same part (e.g. 1x2 tile with or without grooves). Also, some parts have more than one part number, sometimes because of a part being reissued or having some minor internal redesign. By exploring these differences in the catalogue you can sometimes find an alternative part which looks the same but in greater quantities and, therefore, at a lower price. Basically, I use LDD as a design tool and a way of compiling a parts list, but I rarely stick faithfully to this list when making Bricklink orders.
  7. MOC - Garden Toy Train - 12-wide

    It’s supposed to but I’ve never found it to work. If there is any single brick in your build that is not correctly described in terms of it’s shape, colour or part number, or if a part you have used does not actually exist, it will throw the whole list out. You may say that this should not happen given that LDD is the official software released by TLG themselves, but it’s all too common in my experience. If you want to try I believe that Bricklink gives you the option to upload to the website rather than it being an option within LDD. It’s so long ago that I last tried it that I can’t honestly remember all the details.
  8. MOCer's will you buy the new train sets?

    Nope. I think you’re going through the same process I went through. The more I visualise, design and build the less I wish to buy TLG’s official offerings. Surely the whole point of LEGO is that you can build whatever your mind can imagine.
  9. 2018 Speed Champions Sets - Rumours and Discussion

    I'm not really a set builder, but I did pick up the Mustang, Fiesta WRC and Porsche 919 at the weekend from my local supermarket. I'd been toying with the idea of getting involved with the Speed Champs theme for a while but nothing had tickled my fancy before. I have to say that the Mustang is my new favourite thing. It looks cool and the colours are great, and I even applied the stickers (got to love those gold stripes on green and black). Given the limitations imposed by using LEGO bricks I think they've done a great job of capturing the shapes of the original. If anything some of the details, like the tail lights, could have ended up as a sticker, but they've actually bothered to design them to be built in brick!! I'm not at all disappointed with it. All three sets were satisfying to build, and I guess it's unavoidable that racing cars will require a whole load of stickers. But taking my time to ensure that they were all correctly positioned paid dividends and all three models look very sharp. If I had to make any criticism it would be that the proportions of the Fiesta are wrong, but apart from that the essence of the car is still there. Will I be buying more Speed Champs sets...? Quite probably.
  10. Train MOCs and Builders - Who/What is Your Inspiration?

    I take my inspirations from what I see around me rather than from specific builders or models. Working on the railways gives me plenty of exposure to lots of interesting prototypes as well as an understanding of function as well as form. I often look at different things and wonder how I might make them in LEGO. Many of my ideas fail to get beyond the thinking stage, but some ideas show more promise than others. Apologies if this is not in keeping with the ethos of this thread.
  11. Unfortunately my soldering and programming skills are not up to your high standard, so I would hope TLG could make the various components cross-compatible straight out of the box. But still, we’re only at the very early stages of discovering the PF 2.0 standards, so I guess this is all a very long way off (and probably the basis for a separate thread in a more appropriate forum).
  12. OK. Thanks for the insight. I was just idly wondering what a common plug standard might mean and how PF, Mindstorms and other systems might be made to work together. I guess that’s something for the future.
  13. Just as an aside... Does this mean that there might be a Mindstorms v4 in the pipeline or just new plugs for the existing ev3?
  14. Rolling Bridge

    Another intriguing solution from outside the box. You clearly have a very fertile imagination.
  15. MOC - Lego Clockwork Locomotive #3

    Sounds like you've found a good combination of parts to make it work so well. That's excellent!! And yes, I can confirm that your lamp code is correct.