My 4-8-8-4 Big Boy Locomotive

[someguy]

Last year I got back into building with Lego and I decided to go from never building anything complex to building something extremely complex. In January 2014 I started researching how to build a Big Boy out of lego. Five months later, 3 LDD files, and A LOT of random train car designs I finally started ordering parts for the engine! Thankfully before Christmas I was able to complete the engine. However, it did not run......it spun the wheels quite well though! This engine is not my design however, I found the instructions online and changed some things that I thought made it look better. The tender is my own design, I did not like the tender in the instructions. I still want to get a shorter technic piece for the coupler from engine to tender and tubes that run along the top sides of the engine.

Here are some pictures of my engine. Some may be a bit small. Here is an imgur link with full size pictures. http://imgur.com/a/5b5PF

This is the inside of the boiler. It is just a bunch of technic 1x's and holds 4 PF M motors.

The front wheels are quite close to the drivers and cylinder.

I created a simple stand for the boiler so it would be easy to work on without it constantly rolling everywhere.

A MOC I designed. Goes with the Alien Series 13 minifigure.

The engine crew!

Inside the Cab

Some overall shots. The drive rods are only on 3 wheels each side because the front drive rod hits the rear cylinders and the rear drive rod is too wide to get past the rear cylinders. I plan on ordering custom steam rods which will resolve these problems. I also used some silicon on the gears which drys quickly and keeps the surface slick, making for much smoother running.

Just a MOC fire station I am working on.

Here's 10 pounds of bacon for reading my post!

Edited August 30, 2015 by someguy

[legoman666]

Looks good!

I think I followed the same set of instructions. I ended up modifying the transmission, drive rods, and leading 4 wheels and training 4 wheels a lot in order to get it to run smooth. Still has slight problems with traction in the nadir/valleys of uneven track segments. I also added some more greebling and switched the motors to large. Runs OK all in all. Wish I could put the battery weight on the drive wheels.

[someguy]

Looks good!

I think I followed the same set of instructions. I ended up modifying the transmission, drive rods, and leading 4 wheels and training 4 wheels a lot in order to get it to run smooth. Still has slight problems with traction in the nadir/valleys of uneven track segments. I also added some more greebling and switched the motors to large. Runs OK all in all. Wish I could put the battery weight on the drive wheels.

Same here. I recommend off seting the connecting rods by 90 degrees on both sets of drivers, this helps stop them from binding. Also, have a really close look at the leading wheels. I had to modify mine because they scraped the front cylinders on turns and would grind badly. If you need more traction try rubber o-rings from your local hardware store from a toilet o-ring kit. but only use o-rings on 1 axle per set of drive bogies.

Would you say yours is significantly faster switching to L motors?

Edited August 30, 2015 by someguy

[ecmo47]

Mmmmm...Bacon.....

Are the side rods complete? There are some obvious missing parts for full functionality.

Who is selling those plans? I've not stumbled across them yet and would like to do this project. Thanks!

[THERIZE]

I believe zephyr1934 sells custom rods.

[someguy]

Mmmmm...Bacon.....

Are the side rods complete? There are some obvious missing parts for full functionality.

Who is selling those plans? I've not stumbled across them yet and would like to do this project. Thanks!

The side rods are not yet complete. What happened was in August 2014 I had to start classes again and I just now took the engine back out to get it working. The problem is on the rear set of drivers the current connecting rods stick too far out and hit the cylinder when connected to front wheel so I cannot connect all 4 axles. Same problem on the front set of drivers. The conecting rod, if connected to the rear wheel, hits the rear drivers cylinder around turns and causes a derail. I plan on buying custom connecting rods and driving rods hopfully soon.

I didn't buy the plans, but I can post links here for them! I found them on youtube with a link in the description. Just use microsofts snip tool to get the picture if it wont let you copy them.

Just a warning though, there are some things I found on the plans that I did not like or had to change to make the engine stop derailing and run better. Also, I did not use the tender from the instructions.

Just to be clear, these are not my plans and I do not take credit for them. According to the youtube video description the instructions are Scott Mills inspired by JayHurst.

http://www.brickshel...ry.cgi?f=533320

Here is my original post when I was still in the planning stage. Hope this helps with your planning as well.

http://www.eurobricks.com/forum/index.php?showtopic=93035&hl=steam+engine+4884

For more inspiration see below!

Nebraska also just built a Big Boy and it is very nice!

http://www.eurobrick...howtopic=113369

Also see the 844 by Nebraska

http://www.eurobrick...=+steam +engine

http://www.eurobrick...98#entry2051832

Edited August 31, 2015 by someguy

[Barduck]

I've used the same plans to do mine and then changed the mistakes in it to be more like Jayhurst one. But mine is being powered by 4 (yes FOUR) XL motors. She might be slower but the raw power she puts out is crazy

[someguy]

I've used the same plans to do mine and then changed the mistakes in it to be more like Jayhurst one. But mine is being powered by 4 (yes FOUR) XL motors. She might be slower but the raw power she puts out is crazy

How did you ever fit 4 XL motors on that thing?!?!? (Both surprise and confusion!)

Could you PLEASE make a topic with pictures? I tried to put 4 XL motors in it on LDD but my skill is not yet high enough. Will also help me with my next engine build!

(Sorry if there are some terrible spelling mistakes. I am on my phone and it's hard to see.)

[ecmo47]

Thanks for for all those great links!

One question: how do you power 4 motors?

[Barduck]

How did you ever fit 4 XL motors on that thing?!?!? (Both surprise and confusion!)

Could you PLEASE make a topic with pictures? I tried to put 4 XL motors in it on LDD but my skill is not yet high enough. Will also help me with my next engine build!

(Sorry if there are some terrible spelling mistakes. I am on my phone and it's hard to see.)

with love, blood sweat and tears, lol. Seriously though, it's not hard, just takes some try and error

[someguy]

Thanks for for all those great links!

One question: how do you power 4 motors?

I just use 1 battery box. But from what I have heard Im not getting full performance out of them. I would need a v2 IR sensor and rechargable battery box.

[zephyr1934]

I just use 1 battery box. But from what I have heard Im not getting full performance out of them. I would need a v2 IR sensor and rechargable battery box.

At least in my experience I have had no problems with two XL motors, one conventional IR sensor, and one rechargeable battery box. I only run into occasional overload problems with a pair of PF train motors. I bet a pair of XL motors would be all you need in the Big Boy to meet your power needs... that is if you can figure out how to get them in there.

In any event, looking good! I like that you showed the progression as well as the behind the scenes tools necessary to pull it off. So how did you do the centipede tender wheels? One of the things you could do while fine tuning the rods are to use half thickness technic beams stitched together to make a longer full width beam (and thinner in the spots where you need it), e.g., as done on this engine. Though you might have meant that you had less than a half beam's clearance.

[someguy]

name='zephyr1934' timestamp='1441406754' post='2321454']

At least in my experience I have had no problems with two XL motors, one conventional IR sensor, and one rechargeable battery box. I only run into occasional overload problems with a pair of PF train motors. I bet a pair of XL motors would be all you need in the Big Boy to meet your power needs... that is if you can figure out how to get them in there.

In any event, looking good! I like that you showed the progression as well as the behind the scenes tools necessary to pull it off. So how did you do the centipede tender wheels? One of the things you could do while fine tuning the rods are to use half thickness technic beams stitched together to make a longer full width beam (and thinner in the spots where you need it), e.g., as done on this engine. Though you might have meant that you had less than a half beam's clearance.[/b]

Thank you, took a long time to get a design I like and it was torture waiting for the parts. I wanted to put bigger motors in before I built it, but now that it's up and running I am very happy with how it performs. But my next engine will use bigger motors. :)

Yea I didn't realize while building it how close the clearances would be in turns. It has a half beam clearance, but I am waiting to buy some custom rods. Mostly I want to see how it performs on a large layout at a LUG convention since the custom rods are so expensive. Plus I want to make sure I worked out the bugs regarding the rods binding up.

The tender was a bit of an annoyance at first. Seen below every axle can turn by itself. The 2 on the far left look connected to that bogie, but underneath are 2 turn tables to provide lots of freedom for it to move. I quickly found out that by doing this the axles would go around turns the wrong direction and then would not go back to straight and would just drag along sideways. The problem is the technic piece sticking out acts like a toothless gear forcing the other axle to turn the opposite direction, so every other axle would be facing a different direction.

To fix this I simply 1/3/1/3 bricks connecting the( from the right) 4-5 and 6-7 axles. Now these go around curves like normal bogies under a trailing car. The 3rd axle is still free to move but the toothless gear action caused on it by the 4-5 connected axles forces it to turn in the right direction.

The connections with the 1/3 pieces are weak, but since I made my own tender, which is crazily heavy, the tender easily holds everything in place. If you have a look at my next engine design I am using the same idea on the tender. This time though it's more even on both sides so more of the tender stays over the axles around bends. ex: above 2-2+2-2+2 2-2 next tender 2-2+2-2 2-2+2-2 '-' means connected axles to solid frame, '+' means connected axles by hinge. If this is confusing just ask and I can post pictures lol. Also, this tender goes around curves so smoothly now it's insane! I put a pf train motor in place of the front bogie and I could go full speed around my layout without it tipping over and flying off on curves. Unfortunately I found out it will throw my friends Santa Fe engine off the table at full speed.

Edited September 5, 2015 by someguy

[Dutchiedoughnut]

Nice job on the tender axles :). It looks like it'll be longer than any engine I'll ever build ;)

[legoman666]

I built from the same instructions as you, I figured out that the binding was caused by the fact that the axles coming down from the motors drive blind wheels, which then transfers power to the flanged drivers via the driving rods. I added gearing inside the trucks to transfer the rotation from the motors to each driving axle. I can post a photo of my explanation isn't clear.

[someguy]

Nice job on the tender axles :). It looks like it'll be longer than any engine I'll ever build ;)

Thank you! It's a lot of fun building big engines though, definitely worth a try.

I built from the same instructions as you, I figured out that the binding was caused by the fact that the axles coming down from the motors drive blind wheels, which then transfers power to the flanged drivers via the driving rods. I added gearing inside the trucks to transfer the rotation from the motors to each driving axle. I can post a photo of my explanation isn't clear.

On my engine the drive shafts drive the flanged wheels. I am curious how you transferred power to the other axles though, I think it would help take some stress off the driving rods. If you could post some pictures that would be awesome!

[zephyr1934]

On my engine the drive shafts drive the flanged wheels. I am curious how you transferred power to the other axles though, I think it would help take some stress off the driving rods. If you could post some pictures that would be awesome!

Good call powering a flanged wheel. I'd suggest only putting traction bands on one pair of wheels per wheel set. If you have two they are more likely to fight one another in a curve. In this case all of the other wheels are powered by the rods, but none of those wheels actually pulls any load.

[legoman666]

Thank you! It's a lot of fun building big engines though, definitely worth a try.

On my engine the drive shafts drive the flanged wheels. I am curious how you transferred power to the other axles though, I think it would help take some stress off the driving rods. If you could post some pictures that would be awesome!

Sorry for the delayed reply, my trains were packed away.

You'll note that the point at which the turntable and drive axle attaches is in the middle of the two powered axles. The instructions did not have it this way. When you go over an uneven track section (like a small peak), the whole truck will have the tendency to twist. With the leading set of drive wheels over the hump, they will twist out of the track. With the drive axle coming down in the middle, this will not happen. Thus, both sets of drive wheels end up BFBF. Instructions show both as FBFB.

Edited September 19, 2015 by legoman666

[LEGO Train 12 Volts]

To maintain straight also last axle of wheels I have adopted this similar kind of solution:

[someguy]

name='legoman666' timestamp='1442625323' post='2334291']

Sorry for the delayed reply, my trains were packed away.

You'll note that the point at which the turntable and drive axle attaches is in the middle of the two powered axles. The instructions did not have it this way. When you go over an uneven track section (like a small peak), the whole truck will have the tendency to twist. With the leading set of drive wheels over the hump, they will twist out of the track. With the drive axle coming down in the middle, this will not happen. Thus, both sets of drive wheels end up BFBF. Instructions show both as FBFB.

[/b]

Thanks for the info legoman666. I'll have to see about changing mine so it wont derail on slopes.

name='LEGO Train 12 Volts' timestamp='1442641895' post='2334453']

To maintain straight also last axle of wheels I have adopted this similar kind of solution:

[/b]

That's exactly how I have my tenders axles set up, only difference is I use bogie plates instead of turn tables. With the axles set up that way the tender runs extremely smooth.