I think the best location for a webcam would be one which gives a similiar view from the Port Wakefield Rd bridge at Cavan
. A camera in a similiar position, facing south-west, would allow people to view locomotives in the Dry Creek Motive Power Centre, and see lash-ups being moved from the MPC under the bridge into Dry Creek North as trains consists are put together, plus any south line grainies would be seen departing (along with Aurizon PM services). On top of that, it would capture all standard gauge movements heading into/out of Adelaide from the Western mainline, plus metro trains on the Gawler, and the broad gauge 'stonie'.
A second camera in the same position, but facing North
, would give a great view of Dry Creek North yard, which is where GWA grain train consists are put together. Such a camera would be a great heads-up for chasers. A quick view of the webcam would indicate if a grainy was due out soon, as generally the locomotives will transfer from the MPC to Dry Creek North well before departure.