Emerson (SA) signalling panel

[Eddie Oliver <eoliver@efs.mq.edu.au>]

The Port Adelaide museum includes what seems to be an NX panel which
controlled facing and trailing crossovers at Emerson (just a couple of
stations from Goodwood towards Noarlunga). I could see no explanatory
details, and because the lighting above the display had failed, it was
hard to see much anyway. Can anyone cast any light on the history of
this panel - when was it in use, did it just control terminating
movements or was there full bidirectional signalling involved, and
(above all) why did it exist at all - it seems to be a most unlikely
place for such an installation?

Eddie