Duplo Trains discussion

[zephyr1934]

The original lego bricks were based on a British design, Kiddicraft that dates to 1945. One would have to dig up the Kiddicraft patents to find out what dimensions they were originally drawn in.

As for the technic holes, the 1x1 brick came along fairly late in the game (1993). The 1xN technic bricks were introduced in 1977, but the technic holes date to 1970 and this brick,

which looks like it was initially introduced to update the gears (the big red, yellow and blue gears).

Their predecessors were these, dating to 1965

that would simply be pushed on to the 2x2 wheels or 4x4 turn tables. So the vertical center position of the technic hole probably matches that of the old wheel holders,

[Robert Cailliau]

Hi Zephyr1934,

Yes, interesting new (to me at least) ideas.

But let's move this to the other topic, it's really not about Duplo trains any longer.

If you post it again on

http://www.eurobrick...showtopic=94841

I'll reply more extensively there.

See you onver there,

Robert.

[dlo]

We play A LOT with Duplo at home and I am inclined to get some trains, although the one thing holding me back is the sound effects. Does all Duplo trains make sounds? Can you modify them to turn of the sounds?

If anyone got the answer, I'd be really glad.

[Robert Cailliau]

I suppose you could open up the locos and then cut one of the wires to the little speaker. Not advisable if you don't have enough tools or experience.

However, they don't use much for sound effects: once in a while they blow the whistle, rarely. They do so when you push the start button, and also when they reverse direction (the ones that can do it). They gurgle when you "fill them up". But that's all. So it's all fairly quiet.

[cortex31]

Hi all

I am stuck with the APR question for a while now and even if I found some very interesting mathmatical instight here, I still can't figure out how to build a APR track with exactly 4 switches.

Does one of you even made it ? or is it just impossible ?

thanks for your help

Edited October 21, 2014 by cortex31

[Robert Cailliau]

Here is one:

The crossing can be a level crossing or it can be a bridge, it does not matter.

Edited October 21, 2014 by Robert Cailliau

[cortex31]

well, I came up with this design earlier, but, by trial and errors, I found out that it was not APR, maybe I did not but switches in the right orientation.

Would you mind telling me which side of each switch is the forking side ?

Or maybe the starting point of the train is important ?

Ot maybe Imiss understood the APR consept. It is that each point of the track is reachable without any manual switching, right ?

thanks

[Robert Cailliau]

APR means you can get from any point in any sense to any other point in any other sense by only manual switching.

I.e. you can set the switches, but you cannot pick up the loco to move it to another place, or turn it around, and the loco also can only travel forward, it's not allowed to switch into reverse.

[cortex31]

well, it seems that I just miss understood it.

What I'm looking for is a track layout were the train will go everywhere byitself, relying on the automatic switch of the switch when the train goes in reverse direction through it.

just like the description here for a two swiches layout (last drawing of the first figure):

http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Mathematics/2013_October_14

does anyone ever throught of such tracks ?

[Robert Cailliau]

Now that is an interesting but different problem.

As I'm still thinking about a suggestion from Peter Nolan, I'll leave yours for even later.

You possibly need a few more conditions, such as: is it OK if the train goes over everything but then gets trapped in a loop? Or does the train have to go through everything and return to its original position? Etc.

[cortex31]

I'm thinking of something with no trap loops, in this case, I guest that the train will have to come back to its original position after some time (short or long, could even be infinit...) but I don't even know if it can be possible with more than two switches...

It may require some High level mathematics...

[Daedalus304]

I don't know if it`s what you`re looking for, but on the track design Robert posted, if you have both the left OR both the right switches flipped to turn then your train will on its own travel across all the track and end up back at its starting position. It is one of my favorite setups for its simplicity and variety.

[cortex31]

well I can't figure it out :-(

would you have a drawing of that, with switches in and out labeled ?

thanks

[Guy_Walker]

I did investigate this problem a few years ago.

The circuit you describe is this:

The train traverses all the track automatically, without human intervention to switch the points.

I call this an ‘All Points Visited” (APV) circuit. The train sets off and covers all the track, visiting all the points, eventually returning to its starting position.

As Robert says this is quite a different problem than APR (All Points Reachable)

Now that is an interesting but different problem.

As far as I can tell, no other circuit than the one above exists.

Adding more points cannot create an APV circuit. Either:

1/ The train enters a trap. At best this will require human intervention to switch a point and allow the train to ‘escape’. The circuit may be APR but not APV.

Or the train does manage to traverse a large loop but

2/ Some points are never switched by the train. They will have track that is never traversed. The points and associated track are redundant and can be removed. The complex circuit quickly reduces to the layout above.

Large APV circuits can be built but you need to also use some different types of point (sprung, flip-flop etc)

Edited October 30, 2014 by Guy_Walker

[Daedalus304]

Yes, here is his picture with a couple arrows drawn on it:

Setting the switches like this WILL have the train cross every single section of track. It's a big track plan, and it's fun to watch. If you have the train start from either straightaway going left, it will eventually end up right back where it started. If you have it travel to the right, it will still cross every section of track but will not face the way it started.

[Robert Cailliau]

Gentle people, this is VERY interesting.

However, I think it should go to a topology/mathematics forum (though it does not mean we can't have fun with it right here!).

And I sincerely wished I had more time right now to explore these problems, but I'm too busy.

Two small points (I'm short of time):

(1) has anyone tried the gear meshing calculator I posted?

(2) how about this one I built last Sunday:

to help a friend understand why solar eclipses and lunar eclipses often occur close together

(sorry for the styrofoam balls representing the Sun, Earth and Moon)

Edited October 29, 2014 by Robert Cailliau

[cortex31]

daedalus, the circuit you show is not (in my pont of view) an APV circuit. It would be if switches were not modify by the train when it goes through it in the opposite direction, but it seems to me that in duplo there is no such switches...

Guy_walker, I was affraid that the answer would be that there is no such large track layout... I guess I will have to stop looking for it and go for an only APR track

Edited October 30, 2014 by cortex31

[Guy_Walker]

An APV layout was one of my dreams too, but no it cannot be done

However, you do suggest the way forward…

it seems to me that in deplo there is no such switches...

You need to make 'Sprung' points

In theory … Duplo points (which are correctly called Lazy points) can be modified. Some kind of spring or elastic band needs to be added to keep the points in one position while allowing the train to pass over undisturbed. The points move just enough to let the train pass before springing back.

In practice it’s difficult to get right. But I feel sure it could be done.

Here is a circuit using only Sprung points. The spring ensures that the train only exits on the straight line, never the curved ‘branch’ line

The train joins the main loop and then visits each ’sub layout’ 1, 2, 3 in turn. The train always returns from each sub layout back along the same track. There is even a bell to alert the operator to the start of the next loop :-)

I think you can see the similarities with a computer program, where each sub layout can then ‘call’ other sub layouts etc etc. So you end up with a multiple branching tree-like structure

So this technique will allow you to build large APV track layouts...

[cortex31]

sound great

I may try something like that if my son let my ply with his train....

[Robert Cailliau]

cortex31:

If you look at http://www.cailliau.org/Alphabetical/L/Lego/Duplo/Train/Rails/Switches/ you will see that the old Duplo switches did remember how they were set.

You can buy old switches cheap on the net. The new switches have been "dumbed down", have fewer parts and are probably easier for kids to operate.

There are therefore two types of APV tracks: with switches that remember and with switches that do not.

What a very interesting set of problems. Good luck…

[Guy_Walker]

Ah ha - thankyou Robert. I think I remember reading about old points some time ago

This makes the terminology kinda neat. We’ve got ‘new’ ‘lazy’ switches that remember and ‘old’ ‘sprung’ switches that do not

So no need for elastic bands. Just use the old type of Duplo points to make large APV layouts

BTW if you mix old and new points you can build computational traintrack layouts. I have some track layouts that can calculate triangular and Fibonacci numbers. Takes quite a lot of points though…

Edited November 1, 2014 by Guy_Walker

[Robert Cailliau]

Ah ha - thankyou Robert. I think I remember reading about old points some time ago

This makes the terminology kinda neat. We’ve got ‘new’ ‘lazy’ switches that remember and ‘old’ ‘sprung’ switches that do not

So no need for elastic bands. Just use the old type of Duplo points to make large APV layouts

The other way round perhaps? the old ones did remember their setting, the new ones do not, i.e. if you let the loco go, then after a while you can still see how the old ones were set, but not how the new ones were.

BTW if you mix old and new points you can build computational traintrack layouts. I have some track layouts that can calculate triangular and Fibonacci numbers. Takes quite a lot of points though…

I seem to remember reading about a discovery of an extremely complex model train layout in the attic of some manor house, with the only explanation offered that it was a computational device in disguise. But it may have been an SF story, my memory is not too good.

But wow. How many points for Fibonacci?

b.t.w do you know about LiveCode?

[detjensrobert]

I have some track layouts that can calculate triangular and Fibonacci numbers. Takes quite a lot of points though…

I always knew Duplo was good for something...

[Guy_Walker]

The other way round perhaps?

oh OK hold on -the terminology has already got confused !!

I’m using ‘remember’ to mean the switch remembers the last line the loco arrived on. It has a memory - which is important for computing. The new switches do this. Whereas you mean the switch ‘remembers’ how it was set by human operator. Which is what the old ones do.

I can see both views. Maybe best if I avoid the term ‘remember’ to describe old and new switches.

The Fibonacci layout requires around 60 points plus around 40 points per stage at a quick count. The layout is modular so stages are just duplicated to allow for larger binary numbers.

The complete image will bloat this post badly. But here is an example of a counter function.

The train increments the counter each time it visits before returning back along the same track. It needs 1 new and 3 old points per stage. All new points start in position ‘0’ as shown and are switched by the train to show a binary ‘1’. Old points always switch to the straight track. Track 'e' indicates an overflow error.

I played around with LiveCode for a while but then stuck with Javascript because I could build code straight into a web page.

You might like this.

http://www.cr31.co.u...wang/stage.html

If you select ‘Rail’ from the ‘2-edge’ pull down menu you get random rail tracks. Click the lower ‘Maze’ button for a more joined up layout. I need to add wandering train sprites.

I will tidy up the complete Fibonacci layout and upload to the website. A 5 stage circuit will fit on a web page. I really want to add some explanation as to how it works, otherwise it can all end up a bit meaningless.

UPDATE: Uploaded triangular and Fibonacci calculating layouts as well as a random number generator to cr31 site. Use the above link and click the 'Trains' tab. The DigiComp emulator will be added soon.

Edited November 17, 2014 by Guy_Walker

[Robert Cailliau]

To Guy Walker:

Yes, this certainly heads to a different site altogether.

Agreed about your terminology.

Fascinating. I explored cr31.co.uk a little. Well beyond what I have time for right now. :-(

You are also right that it's necessary to be able to write programs directly to a web page. There was a LiveCode plugin, but plugins are no longer "allowed". Hence the project of html5 at LiveCode, so it will be possible again in the near future through a different technology.

The story of programming in the web is (to me) a sad one, but also not for this forum. Perhaps more via robert at cailliau dot org.

To the others: sorry for this digression.