Hi everyone,

First of all allow me to put this topic in context: I’m submitting you this MOC attempt to collect your solutions and opinions about my bogie and piston setup that does not work at all.

So please forget about the ugly boiler and cheap and dirty look of this model, especially after the amazing post of Murdoch17 . It is just an long 7710 build to put some weight on the wheels and give some chassis rigidity.

I’ve been looking around the web for different solutions but did not find something that really fit my needs.

Let me list the things I dislike or want to improve on the model :

As you can see, the pistons are much too far from the head of the Loco. I simply could not move them forward as they would prevent the “4” bogie to move laterally.

Talking about the “4” bogie, it just moves way too far laterally, as you can see it goes beyond the 6 sutds width of the loco. So the whole model is actually completely unstable in the turns. At medium speed, it just jump out of the track.

I was rather happy with the design of the central “6” bogie. It is compact and rather well proportionated. BUT when putting it on track, it turns out that putting the blind wheel in front to hide it behind the piston, was a mistake. It seems to increase the lateral move of the front of the loco and leaks in stability.

My first thought was to remove the rubbers around the big wheels, in order to prevent power to be lost in putting the piston bars in action. I also did not put the left and right wheels on a single 6std technic axel in order to allow differential speed on the inside and the outside of a turn. All this seems to be also a mistake as finally nothing moves and the piston bars tends to get blocked straight away.

Finally, I also had difficulties to have everything “flat”: it is not easy to compensate the wheels differences ( with and without rubber). Actually even plates are too tick.

So this is it: this model is rather unstable not well proportionated (regarding the piston position) so please, if you have some expertise to share (and I know you have :-) ) , please comment.

I’m really wondering how you guys worked out those issues.

Edited March 31, 20159 yr by PasDeChocolat

First off, I don't think it looks cheap or dirty, just vintage with a bit of loving wear and tear. Also, thanks for the mention!

Anyway, the wheels have to be flanged, blind, flanged, other wise it won't go round curves at all. That could be your first problem.

Best of luck on the model, and keep on steaming!

And you must have at least two axles mounted on six long axles. It is essential that on a steam engine both sides turn together exactly. You also need to make sure the rods are 'quartered' That means that when on one side the rods are at the bottom (6'o clock) position the rods on the other must be either at the 3 o'clock or 9 o'clock positions - i.e one quarter of a circle difference. If this is not accurately maintained then the rods will bind and lock up.

Anyway, the wheels have to be flanged, blind, flanged, other wise it won't go round curves at all.

Sure! I'll start with that. Lets do the obvious first .

By the way Is there a best position to place the pivot point of the "4" bogie?

It is essential that on a steam engine both sides turn together exactly. You also need to make sure the rods are 'quartered' If this is not accurately maintained then the rods will bind and lock up.

OK! Fisrt big learning for me : I allways tought that rods had to be opposite: left on 6h -> right on 12h but indeed it tends to naturally block. I must say that is the first time I hear about that. Never seen something on the net about it.

It is maybe too obvious... but to me it was not .

You also need to make sure the rods are 'quartered' That means that when on one side the rods are at the bottom (6'o clock) position the rods on the other must be either at the 3 o'clock or 9 o'clock positions - i.e one quarter of a circle difference. If this is not accurately maintained then the rods will bind and lock up.

That is the best piece of Lego train information that I have learned for the entire month of March. Time to make some changes to my MOCs.

I love the look of this train too - very vintage, and very cool.

As others have said, if you swap the first and second driving wheels (so that the blind wheels are in the middle) then the loco won't have such a sharp angle when it goes around curves.

For the bogies, the wheel axles are based on a 2 x 4 brick. Is it possible to join these bricks with a 2 x 6 plate underneath, instead of from above? If that's possible, you could then remove the lift arms from above the axles, and relocate your bogie pivot in between the two axle bricks.

Another option, which really retains the Classic Train look, is to use the sliding wheel linkage bricks bb36 and bb37. This allows for a bogie setup similar to the 4.5V set 182: http://www.bricklink.com/catalogItem.asp?S=182-1

Edited April 1, 20159 yr by Richfilth

For the bogies, relocate your bogie pivot in between the two axle bricks.

Yes, you make me think about it and definitely this will improve the behaviour. I'll work on that too.

Another option, use the sliding wheel linkage bricks bb36 and bb37

For that point, As I'm planning to improve the look of this loco drasticly, I prefer to go of a "modern" technic option.

Anyway thanks for the advices , I'll try to implement that asap.

Edited April 1, 20159 yr by PasDeChocolat

Hi there. I have been working on a 4-8-4 Northern (the Chessie Steam Special) since January and it has certainly been a challenge since It is my first big steam engine. The biggest thing I have learned so far is that there is nothing like good old trial and error to get everything to work smoothly. I don't think anything that I tried worked correctly the first time...

I experienced issues with my pilot truck, the front "4", also. I ended up having to spread the wheels apart further than I would have liked to get them to clear the cylinders.

The biggest thing I have learned so far is that there is nothing like good old trial and error to get everything to work smoothly.

Completely agree. I’m far from being able to build a working MOC in LDD. I also prefer to play with the bricks and mess around.

I experienced issues with my pilot truck, the front "4", also. I ended up having to spread the wheels apart further than I would have liked to get them to clear the cylinders.

Indeed. Until now, I identified tree ways to do get a 4-x-x working:

1) The pistons are part of the central bogie. That allows having that bogie on a pivot point. Maybe it helps going through curves.

Of course it is best suited for a non-motorized loco. I personally prefer that solution for a 2-x-x so that the front of the train is not too long as I did.

2) If I understood well, there is your option witch consist of having the pistons are in-between the front and rear axle of the “4” bogie. This is the option I personally prefer

3) Simply have the pistons above the wheels of the “4” bogie. I don’t really like that option, I find it visually unbalanced.

4) Anyone other options ?

One think I’m also considering, is going for 7st width, as it will allow more confort for lateral movement of the bogies.

Edited April 3, 20159 yr by PasDeChocolat

Indeed. Until now, I identified tree ways to do get a 4-x-x working:

1) The pistons are part of the central bogie. That allows having that bogie on a pivot point. Maybe it helps going through curves.

Of course it is best suited for a non-motorized loco. I personally prefer that solution for a 2-x-x so that the front of the train is not too long as I did.

2) If I understood well, there is your option witch consist of having the pistons are in-between the front and rear axle of the “4” bogie. This is the option I personally prefer

3) Simply have the pistons above the wheels of the “4” bogie. I don’t really like that option, I find it visually unbalanced.

4) Anyone other options ?

Not having driving rods at all (or having fake ones) is another possibility: Commander Wolf's 5AT takes this approach.

Option #2 is good, but be prepared to spend a lot of time tweaking the chassis before you start building the body on top. To put functionality first you have to build bottom-to-top.

Hi all,

A happy man is talking to you. I just spent a whole afternoon bricking! I really had a nice time. On top of that I managed to do some progress on my steamer.

Here are some of the ideas I want to submit to you. Please comment if you know ways to improve my solutions.

First, the front bogie: I was not really happy with an arm solution to hold the bogie in place because, in curves, the arm swings to allow the lateral movement of the bogie BUT it also moves the bogie backward. This means the bogie actually moves 2 axes.

To me it was a source of problems. So I investigated a bit and came to a “pivot moving along an axel” solution. It actually has the big advantage that the bogie does not move forward backward anymore. In my final version, it even allows the train to run on non-flat track as it behave as some longitudinal pendular suspension.

IMG_2890 by delaere.john, on Flickr

IMG_2895 by delaere.john, on Flickr

As you can see in the picture above I started with building a sliding pivot in the bogie itself and in between the piston fixation. This did not work well as the lateral movement of the bogie was actually too important. After a few test I came to the conclusion that only one sliding pivot was enough if you place it close enough to the front wheel of the central bogie:

IMG_2908 by delaere.john, on Flickr

Then I looked for a way to position precisely the pistons and the sliding axel in the model. I came up with a rather simple solution as I choose to put both of them on two longitudinal axels. This allows placing both pistons and front bogie exactly where you want them. With that, I managed to build a rather compact solution.

IMG_2913 by delaere.john, on Flickr

For the central bogie I wanted to avoid the friction of the wheels on the frame so I build it in 3 width. I also decided to put it on pendular suspension as the front bogie. The solution allowed too much roll of the suspended part of the chassis so I added two alignment systems, one in the front and one at the rear. I finally added some mean of tuning the wheel height. Really handy for fine setup or to accommodate with adding or suppressing the rubbers:

IMG_2900 by delaere.john, on Flickr

IMG_2914 by delaere.john, on Flickr

Finally I added the rear magnet that I wanted to be combined with the chassis frame so that the push of motorized tender is well repartited…

IMG_2903 by delaere.john, on Flickr

I guess you fell of your chair; yes, indeed, big mistake from me. This solution moves the magnet laterally in curves; magnet needs to be on the last bogie, so I corrected:

IMG_2916 by delaere.john, on Flickr

By now I’m happy with the result. A bit afraid of finding issues when building the top structure or even during trial after finishing everything. But I guess I have no other choice.

I really enjoyed this build, I find my solution a bit original but it seems to work.. for now J. I also appreciated that MOCing train allows to play a lot with technics (that I was practicing quite a bit before to come to train) so it is actually best of both world.

I like the use of technic because they are present in the MOC to really implement functionalities (suspension, sliding pivot...) so my MOC does have some kind of mechanics in it and I like that.

IMG_2912 by delaere.john, on Flickr

All in All, it is far from perfect. Please advise if you see thing that would lead me into trouble.

Edited April 4, 20159 yr by PasDeChocolat

Looks good to me. Great work on this latest update, and keep on steaming!

Now wait a second PasDeChocolat, I thought you said you were new to all of this. (grin) You are doing some pretty sophisticated building there. If I follow your design correctly, the pivot point for the front truck can move left and right on curves, right? That is clever. Now on your adjustable cylinders, after finding the best spacing, after finding the right spot you might want to lock it in place using technic bushings, etc. Otherwise, your assembly will slowly move over time and could eventually cause problems.