  We investigate the topological properties of the helical atomic chains
occurring in elemental selenium and tellurium. We postulate a realistic model
that includes spin-orbit interaction and show this to be topologically
non-trivial, with a topological invariant protected by a crystalline symmetry.
We describe the end-states, which are orbitally polarized, with an orbital
density modulation strongly peaked at the edge. Furthermore, we propose a
simplified model that decomposes into three orbital chains, allowing us to
define a topological invariant protected by a crystalline symmetry. We contrast
this result with recent observations made for the orbital Su-Schrieffer-Heeger
model containing a $p$-orbital zigzag chain.
