  We investigate the kinematics of the molecular gas in a sample of seven
edge-on (i>60{\deg}) galaxies identified as hosting large-scale outflows of
ionised gas, using ALMA CO(1-0) observations at ~ 1kpc resolution. We build on
Hogarth et al. (2021; H21), where we find that molecular gas is more centrally
concentrated in galaxies which host winds than in control objects. We perform
full 3-dimensional kinematic modelling with multiple combinations of kinematic
components, allowing us to infer whether these objects share any similarities
in their molecular gas structure. We use modelling to pinpoint the kinematic
centre of each galaxy, in order to interpret their minor- and major-axis
position velocity diagrams (PVDs). From the PVDs, we find that the bulk of the
molecular gas in our galaxies is dynamically cold, tracing the rotation curves
predicted by our symmetric, rotation-dominated models, but with minor flux
asymmetries. Most notably, we find evidence of radial gas motion in a subset of
our objects, which demonstrate a characteristic "twisting" in their minor-axis
PVDs generally associated with gas flow along the plane of a galaxy. In our
highest S/N object, we include bi-symmetric radial flow in our kinematic model,
and find (via the Bayesian Information Criterion) that the presence of radial
gas motion is strongly favoured. This may provide one mechanism by which
molecular gas and star formation are centrally concentrated, enabling the
launch of massive ionised gas winds. However, in the remainder of our sample,
we do not observe evidence that gas is being driven radially, once again
emphasising the variety of physical processes that may be powering the outflows
in these objects, as originally noted in H21.
