is a sly tug who always finds a way to win. Unfortunately he is always outwitted just at the winning moment and gets in trouble
with Captain Zero.
His hat moves whenever he looks up.
is a mean thug who isn't afraid of anybody. But he is quite confused on the inside, even helping out his rivals the Star Fleet
Zebedee was offered to join the Star Fleet but he refused, saying he is happy being a Z-Stack.
is a loner. He has a croaky voice and an ugly face, making him the scariest member of the Z-Stacks. He is actually quite smart
Zak's engine breaks down easily, sounding like a broken diesel engine despite his steam power.
is quite an ugly tug, and he and Zip are best friends. Zug seems to be the smartest of the two, coming up with ideas that
seem bright but never work.
Zug basically commands Zip, who is too frightened to make any good suggestions.
is the stupidest tug on the Z-Stack fleet. He hangs around with Zug a lot, but is skeptical of his ideas. Zip is easily scared
and cries like a baby when terrified.
Zip never thinks about what he says, often wimping out whenever someone takes offense to his comments.