  Active motion of molecules along filamentous structures is a crucial feature
of cell biology and is often modeled with the paradigmatic asymmetric simple
exclusion process. Motivated by recent experimental studies that have addressed
the stepping behavior of kinesins on microtubules, we investigate a lattice gas
model for simultaneous transport of two species of active particles on a
cylinder. The species are distinguished by their different gaits: While the
first species moves straight ahead, the second follows a helical path. We show
that the collective properties of such systems critically differ from those of
one-species transport in a way that cannot be accounted for by standard models.
This is most evident in a jamming transition far below full occupation, as well
as in non-equilibrium pattern formation. The altered behavior arises because -
unlike the case in single-species transport - any given position may be
targeted by two particles from different directions at the same time. However,
a particle can leave a given position only in one direction. This simple change
in connectivity significantly amplifies the impact of steric interactions and
thus becomes a key determinant of mixed species transport. We computationally
characterize this type of hindrance and develop a comprehensive theory for
collective two-species transport along a cylinder. Our observations show high
robustness against model extensions that account for additional biomolecular
features and demonstrate that even small fractions of a second species can
significantly alter transport. This suggests that our analysis is also relevant
in a biological context.
