  We present evidence from the RAdial Velocity Experiment (RAVE) survey of
chemically separated, kinematically distinct disc components in the solar
neighbourhood. We apply probabilistic chemical selection criteria to separate
our sample into $\alpha$-low (`thin disc') and $\alpha$-high (`thick disc')
sequences. Using newly derived distances, which will be utilized in the
upcoming RAVE DR5, we explore the kinematic trends as a function of metallicity
for each of the disc components. For our $\alpha$-low disc, we find a negative
trend in the mean rotational velocity ($V_{\mathrm{\phi}}$) as a function of
iron abundance ([Fe/H]). We measure a positive gradient $\partial
V_{\mathrm{\phi}}$/$\partial$[Fe/H] for the $\alpha$-high disc, consistent with
results from high-resolution surveys. We also find differences between the
$\alpha$-low and $\alpha$-high discs in all three components of velocity
dispersion. We discuss the implications of an $\alpha$-low, metal-rich
population originating from the inner Galaxy, where the orbits of these stars
have been significantly altered by radial mixing mechanisms in order to bring
them into the solar neighbourhood. The probabilistic separation we propose can
be extended to other data sets for which the accuracy in [$\alpha$/Fe] is not
sufficient to disentangle the chemical disc components a priori. For such
datasets which will also have significant overlap with Gaia DR1, we can
therefore make full use of the improved parallax and proper motion data as it
becomes available to investigate kinematic trends in these chemical disc
components.
