[MOC][WIP] Articulated coach-bus

[Divitis]

Your love for coaches is truly commendable. They are a tad repetitive for my taste, with all these seats, but surely come with some technical challenges.

What I would try to implement, given the space, is some sort of motorized distribution gearbox, so that instead of having one motor for each function, you only need two. One to switch between functions and another to operate them.

 

Even more, you can combine these functions so that only one motor is required. Here's an old solution I put together, which proved to work well and could even handle a good amount of torque. The input (red) connects to either of the two 8t gears depending on the rotational direction. One operates the gearbox (the yellow 'stick' is a shock absorber). The other drives it.

Stud.io: https://bricksafe.com/files/divitis/miscellaneous-/motorized distribution gearbox.io

The trick with the worm gear is best explained here:

 

 

 

22 hours ago, Adeor said:

I really wish you can reply this time. 

 Careful what you wish for. 

Just today I discovered that buses here can lean towards one side, effectively lowering the side closer to the platform to facilitate clumsy humans with a stroller (me) hop on.

I dare you replicate such a feature.

[Adeor]

1 minute ago, Divitis said:

Your love for coaches is truly commendable. They are a tad repetitive for my taste, with all these seats, but surely come with some technical challenges.

What I would try to implement, given the space, is some sort of motorized distribution gearbox, so that instead of having one motor for each function, you only need two. One to switch between functions and another to operate them.

 

Even more, you can combine these functions so that only one motor is required. Here's an old solution I put together, which proved to work well and could even handle a good amount of torque. The input (red) connects to either of the two 8t gears depending on the rotational direction. One operates the gearbox (the yellow 'stick' is a shock absorber). The other drives it.

Stud.io: https://bricksafe.com/files/divitis/miscellaneous-/motorized distribution gearbox.io

The trick with the worm gear is best explained here:

 

 

 

 Careful what you wish for. 

Just today I discovered that buses here can lean towards one side, effectively lowering the side closer to the platform to facilitate clumsy humans with a stroller (me) hop on.

I dare you replicate such a feature.

I doubt coaches can kneel. Plus I got told that since my bus is too big, there is no reason for suspension. Plus due to building techniques, I can only put suspension to 1st and 3rd axle. I really like to include the suspension because it will increase the ground clearance, wich is the width of 1 technic beam. 

Also: 1st and 3rd axle is based on https://rebrickable.com/sets/42110-1/land-rover-defender/
2nd and 4th axle is based on this https://rebrickable.com/mocs/MOC-5161/HallBricks/motorized-bus

[Divitis]

13 minutes ago, Adeor said:

I doubt coaches can kneel.

 

They do. They did for me this very morning 

 

I tracked down the actual bus model for confirmation.

Specifications PDF: Citaro PDF

 

GPT extract:

[ukbajadave]

Not wishing to get too nerdy but a Citaro would be a bus, a coach would be something like a Tourismo. 

And yes, both the Citaros and Tourismos I have driven have knelt.

[Adeor]

Unless I can find a way to rebuild axle for articulated section, because it is based on this MOC https://rebrickable.com/mocs/MOC-5161/HallBricks/motorized-bus I have no clue how to add kneeling and suspension. 

 

[ukbajadave]

Yep. Anything like that pretty much needs to planned before building starts. However, I've just read the thread from the beginning and it seems like you aren't scared of making revisions so who knows what the next version might have 

I didn't realise it has been 4 years since you started! Is it something you do a bit on, then do some other stuff for a while then come back to or are you always thinking about the next build stage?

[Adeor]

Not always. When I built the roof frame for articulated section, I did not even planned it. I just wanted to test off the top articulated ring.

But yes, I started this project 4 years ago but I started with particular MOC last year after several tryouts. 

I found it still most complicated MOC, because there are no high floored articulated coaches/ buses that has instructions. At least I haven't found it. There is Ikarus 280 articulated bus in this forum but again, no instructions plus I wanted to high floored as I wanted to feature luggage compartments under passenger floor and passenger floor with seats - aka realistic as possible. I even wanted to build the nose roof curvy because I found Scania Irizar i8 is my favorite bus but I found it difficult to include the Irizar's head/nose. 

[Adeor]

On 7/22/2025 at 4:51 PM, Adeor said:

Unless I can find a way to rebuild axle for articulated section, because it is based on this MOC https://rebrickable.com/mocs/MOC-5161/HallBricks/motorized-bus I have no clue how to add kneeling and suspension. 

 

Actually I think I figured out the way how to include suspension for my build. It will require partial rebuild of undercarriage and possibly a complete rebuild of the bottom rear of the articulated section. 

[Divitis]

Glad to hear, and looking forward to seeing it!

[ukbajadave]

I think your finished bus may end up well over 10 kg and standard Lego suspension might struggle. It might be better to try and replicate just the ferry lift and tag axle movements. I have a vague idea about using some form of cams. The cams can't be attached directly to the hub carrier but need to slide to avoid front to back movement. In this arrangement the single tan axle drives one end of the carrier (tag axle lift) and the axles linked with gears drive both ends (ferry lift). Using one of the solutions provided by @Divitis would allow both functions to be driven by one motor.

 

[Adeor]

New concept for suspension. 

Drive axle has 8x 6.5L Hard springs. Steering axle has 6x 6.5L Hard springs. With total 4 axles, there will be 28x 6.L hard springs. Links and some additional beams prevent sideways movement while only allow up-down movement. 

Also. This designs also allows sturdier articulated joint. 

New motor configuration would probably use 4x PF XL motors (2 under the articulated joint and 2 at the rear of the bus)

 

[Adeor]

New update. The high-floored articulated coach is generally about 85-90% complete altough articulate section now awaits for rebuild to accomodate springs and new motors.
The build is 145cm long, roughly 10kg heavy and it has about 7000 pieces.

Front section has
* 20x 6.5L hard springs with tight coils at the end for suspension and stabilisation. Previous version had a problem with nose sagging even with additional support at the front axle. With suspenion it has not that problem
* 2x PF XL motors
* Servo motor that connects 3rd and 1st axle unit and steering wheel
* 1x PF M motor for windshield wipers
* Front lights that works
* Lots of seats
* Toilet with a window
* 2 Business class seats with a table
* Functioning steering wheel 
* accelerator and brake pedals

Rear section waits for rebuild to have
* 8x 6.L hard springs with tight coils at the end
* 2x PF XL motors
* Rear lights that works
* Toilet wit a window
* Proper colors

Most difficult system to-be-build (I have no idea how to build these)
* motorized door mechanisms

When completed the coach
* lights, doors, drive motors, windshield wipers and servo motor should be operable using  BuWizz app that is controlled through at least 3 BuWizz batteries
* Opeanable nose hatch
* has finished roof
* has finished cargo bay doors
* has articulated curtain

PS. Don't mind the mess - I am working with a limited space

 

Edited October 8, 2025 by Adeor