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Posted (edited)

Hello everybody,

I am glad to introduce you my last big project : a pneumatic steam locomotive !

I think it's one of the firsts pneumatic locomotives, using only Lego parts.

First of all, the YouTube video and some photos:

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The idea with this model is to replace the steam of a real Locomotive by compressed air, and this for as much functions as possible.

Here are the main functions :

Movement of the train :

Using 4 pistons, 2 on the sides, and 2 inside, the train can move forward. It works like a classic LPE, with 2 pistons shifted 90° from the others. 4 pistons consume a lot of air, but they guarantee enough power to move the whole train. 

6p5u.png

To make the rotation smooth, a free wheel is hidden inside the boiler part of the locomotive. Its rotation is 25 times faster than the wheels of the train (40t/8t x2).

The train isn't moving very fast because the pneumatic elements aren't modified. However, it's fast enough to make it interesting to look at the connecting rods and wheels moving.

The breaks :

On a real locomotive, compressed air is produced by a compressor (powered by steam) and is used to press some brake shoes against the wheels.

Here, the same technique is used : a small piston is filled with compressed air, and thanks to some rods, brakes shoes are pressed against the wheels. 

g4ik.png

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It's cool but...it's not enough. Plastic against plastic isn't very efficient to stop the train's movement. Therefore, another rod is connected to the brake system and press another brake shoe against the free wheel. Because its rotation is faster (and therefore, with a low torque), it's is way easier to stop it.

The Whistle :

A system that I love in this locomotive is the whistle. Currently there isn't any whistle produced by Lego that could be used in the locomotive, so I had to think a little for finding something working. I can give you more details if you want but I used some lego parts that are empty inside and have a small aperture. By blowing air on these parts, we can produce a noise that is a little similar to a whistle noise. 

This whistle is activated by a switch in the cabin.

The Cabin :

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Nothing much to say except that in contains 3 switches for the 3 main functions (whistle, wheel movement and brakes). There is also a pressure gauge showing the pressure coming from pumps. The train moves with a minimum of 1 bar. A 2-2.5 bars, the movement is faster.

The air supply :

There are several possibilities for the train : we can directly pump with Lego pumps, or store the air into 6 to 8 airtanks or produce the air with Lego motors and small pumps. For instance I use 4 pumps side by side, linked to some air tanks, but I don't what the final model should work. Maybe some motors and pumps could be cool ?

The design :

The hard part was to make the boiler of the locomotive. It's a little hard to make cylinders with Lego technic parts but, with flex axles passing through Technic beams, I managed to make something satisfying. 

Some details are visible on the locomotive, I tried to make it look a little crowded like a real locomotive with fake air/sand tanks, fake compressors and mechanical elements. It's probably possible to make it look better, but for instance I am happy with it.

The rails are "homemade" with Lego bricks. The locomotive is too big of course to work on Lego railtracks. The wheels aren't perfectly flat so the train is "blocked" in position inside the rails. Therefore, the train can move foward cur cannot go out of the railtracks (which is great for a train).

Finally, as a bonus functions, there are some bumpers at the front and back of the locomotive to imitate the real bumpers used to absorb small chocs on a Locomotive.

That's it for now, I hope the model is interesting to you and if that's the case, don't hesitate to support it on Lego Ideas ! Click Here to support :)

If you have any question or comment, please reply to the post, I'll be glad to discuss with you !

Edited by alfredboyer

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This is great! I love the whistle!

Are you using this blue Lego air-tanks?

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6 minutes ago, Go-Kart said:

This is great! I love the whistle!

Are you using this blue Lego air-tanks?

Thanks ! :) For storing air I use these blue Lego air-tanks yes.

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This is top notch technic awesomeness, truly. There is so much to see and explore on this train, I really like it.

How is the whistle done?

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This is amazing! I think this is the first time I've seen functioning brakes and sprung buffers in a Lego train. You should also post it in the Train Tech forum to share the awesomeness over there! :thumbup:

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Simply amazing, this is what technic should be all about. 

Very good job Alfred, hats off to your skills and ingenuity.

Trains, Technic and pneumatics, what more could one ask for. 

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From the first look I was wondering why is it in TECHNIC forum and then I got it.

Amazing! This one should go to the technic index!

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I think if this was successful on Lego ideas they could do with releasing a low stiction spool valve. By doing that they could remove the internal flywheel, increase the range and make it move a little faster. They would also probably want to do it as a non-technic set. But for non modified parts this is very nicely done and really like the whistle :thumbup:

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Awesome! This is the coolest thing I have seen in a while.
I like how you use the flex axles and beams to create the cylinders.

And I wonder how is the roadmap of the gas system is running? Or how did the gas tube connect to?

Cool, super cool. Wonder what if connect the train to a bigass gas pump machine.

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1 hour ago, Ivorrr said:

From the first look I was wondering why is it in TECHNIC forum and then I got it.

Haha I agree, I didn't know where to put it too.

54 minutes ago, allanp said:

I think if this was successful on Lego ideas they could do with releasing a low stiction spool valve. By doing that they could remove the internal flywheel, increase the range and make it move a little faster. They would also probably want to do it as a non-technic set. But for non modified parts this is very nicely done and really like the whistle :thumbup:

If it happens it would be awesome since the latest Lego switch seems to be even less suitable for pneumatic engines... In that case, better than removing the fly wheel is to make it smaller, I think it would be still great to smothen the whole movement.

Thanks for your awesome comments and for the front paging ! it's well appreciated :sweet:

5 minutes ago, SamuelYsc said:

And I wonder how is the roadmap of the gas system is running? Or how did the gas tube connect to?

Cool, super cool. Wonder what if connect the train to a bigass gas pump machine.

Thanks ! I am not sure to understand well your question, are you asking how are the pneumatic connected, like the whole connecting plan ? I could make a map of that yeah, here I did it with no plan, except that the left valve controls the right external piston and the right valve controls the left external piston.

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Superawesome. I never thought I'd see such a 'steam'train made from LEGO Technic. And then in such a nice body :wub:, fantastic.

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She's a beauty :pir-love:

Love the ingenious pneumatic mechanisms. I'd be so happy if I could build this in dark green!

I've shared the video on my FB group.

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Wow, this is really impressive from an engineering perspective, and it looks great too. The way you've constructed the outer shell of the loco from beams and flex-rods is so simple and a good way to leave space for all the internals that really make ti move. Very nice that it has a whistle, too.

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Magnificent.  Beautifully designed and integrated.  I love the whistle, and the display on the bit of track you've built is great as well.  :sweet:

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Very impressive.

Several years ago I tinkered a bit with "steam" engines, hoping to eventually put it into a train. But I never did manage to make it move properly. Just couldn't get it turn over smoothly; there was too much drag in the pneumatic switches.

Could you please post more images? I'm especially intrigued by the use of internal pistons and by that big wheel turning over inside the boiler. 

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Excellent build, thanks for sharing. Certainly qualifies for the Technic forum Hall of Fame. The link to LEGO ideas project page does not seem to work for me, supported!

Your choice of track looks great as well and adds to the appeal, rather than using the straight track part 3228c:

3228c.png

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This is really impressive model. I like steam engines very much and this is the first one built from LEGO that I would buy. I am amazed how it works and by your engineering skils.

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I love this, wish there were more Steam locomotive MOCs around.

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An impressive build in every way! Looks amazing and has great functions! I am quite in awe of what you have created. Beautiful work! 

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This is excellent!

If there ever comes an official working set like this one, I'd buy several copies. This is what Technic is all about! Functionality, ingenuity, looks, all in one.

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@alfredboyer So, we will get no insights (whistle, pneumatic layout, etc), or? :innocent: You are playing cheeky girl, there... :laugh:

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