Having made a few posts about the general arrangement and a few details about Swan Hill, I'm just getting around to signalling so it might be a good moment to post the provisional signal diagram "for comment and suggestions" and see what comes up!
Swan Hill is GWR and dates to 1927 (or thereabouts). The track layout is loosely based on a reduced version of Uxbridge Vine Street with the goods yard accessed on a reversal (from road No 3) similar to the arrangement at Windsor central station. Traffic is predominantly passenger and the branch is double track throughout (for a double track branch with nothing much at the end of it, see GWR Uxbridge High Street). As at Uxbridge Vine Street, engines can only run round by reversing stock out of the arrival road (No 2) and running round on the crossover (points 1a and 1b). Parcels, horses, milk and other perishables are unloaded in Siding 1 and the loading dock. Other freight - coal, timber, construction materials and so on - goes to the goods yard via Road No 3. Road No 3 can be used by a push-pull service in addition to providing goods yard access: all three roads have direct access to the Up Branch line.
The layout is wired for DC operation with 4 controller "zones" - the Up sidings (siding 1, loading dock and headshunt) are on controller 1 (C1: coded yellow for wiring). The Up branch is C2 (red), the Down branch C3 (blue) and Road 3 and the goods yard are C4 (green). Switches, relays and a Megapoints servo driver reverse the points, change frog polarity and allocate controllers and track feeds. Thus, reversing point 11 on the diagram allows C2 to take over control from C1 and, similarly, reversing points 10, 23 and 24 allocates C2 to take over from C4. Reversing point 23 causes C3 to take over from C4 (except for the line to the right of point 24) so that access can be obtained from Road 3 to the Down Branch. The same actions remove power feeds to parts of the track so that conflicting moves are prevented. When all points are set normal, the 4 controllers can operate the different areas independently.
What is needed now is signals...