Still working on Airport Equipment...
haven't personally built all the versions and sizes of this one yet
but here is a Baggage Cart and Tractor.
Shown is the 1/100 scale build with the basic Chassis.
I've also provided a two-part chassis with full 3D wheels.
There is also a 1/144 version of the Tractor and Cart with a more simplified construction.
My "test builder" is also working on these, so I'll add his report sometime.
...
Also...
this particular Mobile Staircase was a direct request of my "test builder".
It seemed a pretty daunting task to simplify and create this in miniature paper,
but eventually I figured out a design that I was happy with.
Once again, I have created two versions...1/100 and 1/144 scale.
The 1/144 scale has a slightly simplified chassis, but the Staircase assembly is basically the same.
I couldn't figure out a working Staircase, so I created two options: retracted or extended.
Build it whatever way you wish.
there are also two chassis types, one with 3D wheels, the other with more simplified box construction and 2D wheels.
I built the 1/100 scale versions...both extended and retracted Staircases...
but I used the full chassis and the simplified chassis to show the differences.
My "test builder" also has these models.