Student or Learner
I searched google image and found both of them are big trucks.
But I couldn't find the difference.
What is the difference between rig and juggernaut?
Juggernaut - Definition and More from the Free Merriam-Webster Dictionary
I have only heard the term used in the second sense in AmE. A juggernaut is something that crushes everything in its path, like a great football team.