Lego Duplo 5609

[Kemal Allan]

Another failed example is when you connect two curved tracks in opposite direction. That way the lines entering and leaving the two tracks are parallel. Its tempting to see if you can mount it on a plate. But as it shows again it is not possible.

Why current locomotives do move in only one direction? Would changing the button to a three state switch (forward, stop, backward) make it much more expensive? Or would it be much more difficult for kids?

Adam, i never thought about these issues for a long time, but what i do know is that i also experienced some difficulty in making a nice layout for my son, when we are playing with his Duplo train. For Legotrack it is mainly in my mind what is possible and what not, but for Duplo, it seems that you just start and see how the layout is growing, by adding track... I also found it difficult to make an 8-shape layout.. it is not as easy as it seems...

I really have no answers on your questions, and i wonder if you'll get them here, but i can imagine you are a bit annoyed. Most Duplo builders will not create very complex layouts... so i do not think a lot of people care... they just let their children create something and that's it...

I don't completely follow your question, but the "current" duplo tracks seem to be designed to be mostly curved, including the switches, which are actually just a choice between curve left and curve right.

I say "current" because I suspect Lego just discontinued the duplo trains. They have a new train set, but it just has the four wheel push cars like the ones off of the track at the bottom of the photo above (which happen to run fine on the track as long as you don't have any switches or what not).

Duplo isn't designed for long trains (at least not the powered trains), maybe three cars max. If you have one of the bridges possibly only two cars (at least I think that is what the sets maxed out at). Presumably Lego figured young kids wouldn't appreciate long trains (never mind the fact that that is all my son wants to do) and they also wanted to keep the mechanical power low for extra safety.

One way operation is cheaper, also they now have an automatic detection system to stop if they come off the rails (extra safety). I suspect making that auto stop function work in two directions would have been expensive and less reliable.

Generally no, I don't think they do. But Philo has done an extensive comparison of most of the PF, train, and mindstorms motors (at the moment google is warning that his pages may be a risk, so google "philo lego motor" at your own risk).

The old Intelli-Train does operate in reverse. It works just fine so long as the train is not too long. The Intelli-Train was also multi-speed depending on the driver (one driver was a lead-foot, the other dottering), the state of the fuel tank, and the programming boards. Incidentally, it is a shame that the market didn't embrace the Intelli-Train. The thing is a blast for my kids.

Yes, but that works if and only if you place the track directly on the floor. Once you start placing it on other structures so that they connect to other bricks the flexibility is gone. And now all the non-aligned issues come back to haunt you forever more...

Railcars have fixed wheels (unlike LEGO trains...). This could be explained with lowering costs and making things stronger and harder to break. Sure. But why they are so long? While at the same time curves radius is rather small. And you noticed yourself (and I did see that myself too) that kids like to make long trains.

Now if train pushes rather than pulls it is not connected with railcars. And this leads often to derailments on bridges, curves or switches. Adding a front connector would add a nice opportunity at least partially covering for missing backward move.

Note also that (manual) Thomas line locomotives had connectors on both sides of the locomotive. What is odd however is that they were opposite to what is now so if you would like to connect Thomas line engine to current locomotive it needs to go backwards.

Well, the funny part is that they... don't! To see that yourself you have to mount the tracks on 4x2 bricks (or plates) so that they are not "flexible". Then you will notice that the two curved tracks are slightly longer than two straight tracks.

I had a chance to play with it only once but it was already very old and used. Didn't work well anymore. Buying one now is very expensive and somewhat risky if you buy a used one. But I'm still hunting for one!

I cannot find it. Sure there are some comparisons but they don't include Duplo trains (or it is hidden under code/type name which I don't recognize). Can you please share the link? (Either here or in PM.)

What I do know is that the older rails, black (still for sale as used items on eBay), are the same width but have many disadvantages: they divided the circle in 8 instead of 12, and the sleepers could not fit on plates because the tabs were not raised above the studs. Their surfaces are also a little lower than the new ones.

Using the method of forcing the half-sleepers to unite over a plate or brick, I come to 36.5 for the outer diameter. If you do not use that method, then the play in the connections (we really lack a vocabulary for naming the different parts of rails we are talking about!) will allow for a diameter of 2x18=36.

(4) Another failed example is when you connect two curved tracks in opposite direction. That way the lines entering and leaving the two tracks are parallel. Its tempting to see if you can mount it on a plate. But as it shows again it is not possible.

Indeed. I have a drawing that shows it, for ideal alignments. The play in the connections lets one align straight and snaky tracks, but not if alignment is forced by plates under sleepers. And so maybe that was another important consideration: a snaky track should be able to replace a straight one. For, I suppose you have noticed, most sets have far more curved than straight rails. (a good source of straight rails, used, is eBay)

Perhaps one more thing: I have not yet finished a page on switches. They are different in dimensions from a superposed pair of curved rails. Maybe they have the original curvature. Writing to you has brought this up as a possibility, I will explore it.

Also: the older switches had "memory": if you set one to fork to the left, say, it would stay that way. If a train came from the other direction on the right side of the fork, then it would push the point to the right, but that would bounce back after the train left the switch. The new switches no longer have a spring in them. If you set one to fork to the left, and then a train passed over it in the other direction from the right side, the switch will then be set to fork to the right...

Also the layout page: that is excellent (still have to read it to the end thou). I was thinking about those issues myself some time. But I was going into representing the layout as graph and then see how things look and maybe find some rules.

Anyway I really admire your effort and work. It is nice to know that somewhere out there is someone playing with Duplo rails more than just "randomly". This topic seems to be unpopular, people use System rails instead. Likely I would have done so myself if not having too small children. And since I already invested in much Duplo (mostly rail) it will stay for some time at least.

But is there a way to browse through the topics of the page othrwise than alphabetic? As it has very wide selection of topics while I'm interested in Duplo and LEGO only (for now! ;)). For example I wasn't aware of the very interesting entry in Mathematics...

It does not work with simple graphs, as it is directed. I still have not found a way to get ahead with graphs. I did consult a mathematician on the second problem. He did not get anywhere. However , we agreed (a) it is not a simple problem, (b) I found out it is a property of my algorithm and not at all of the topology or even that it has anything to do with switches. I'll publish on that soon too. I wrote a simple program in LiveCode to do the computation on any matrix, and my algorithm always ends in two steps, no matter which arbitrary set of cells one marks!

Anyway I really admire your effort and work. It is nice to know that somewhere out there is someone playing with Duplo rails more than just "randomly". This topic seems to be unpopular, people use System rails instead.

No. Well, you may ask via Google... I'm doing this site purely to be able to record some of my own thoughts, because writing them up forces one to think straight. And it serves also the purpose of being able to send a URL rather than having to write things again and again.

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