The early days are obscure.
The 1898 GA clearly states that there were no signals at Laaencoorie Junction and the points were secured for the Castlemaine line by a padlock, the key of which was held by the Guard (clearly there was only one Guard on the line). Trains to Shelbourne had to stop at junction so that the Guard could unlock and reverse the points, and, on return, stop again so that the Guard could restore the points and lock them. This instruction for the operation of the points remained for the entire life of the junction - Staff locks were never fitted.
It was standard practice in 1891 for all points on main lines to be protected by Home signals. I don't know if any were provided at the Junction when the Shelbourne line opened, and they were subsequently removed, or if they were never provided at all.
The list of signals at non interlocked places does record two (subsequently changed to three) home signals provided at Shelbourne Junction on 11 May 1911. The Weekly Notice makes it clear that they were normally out of use and crossed. They were only to be brought into use on instructions issued by the GST (i.e. special occasions). The number is interesting. The WN merely says "Up and Down Home Signals" - which could mean two or three, or, again, they could have made a mistake in the list.
The instructions in the 1913 GA were essentially unaltered from 1898 except to state that the fixed signals were normally out of use and only brought into use when the junction was opened as a staff station. (Given this, I'd suspect that the temporary staffs were provided in 1911.)
In the 1919 GA the instructions were augmented. It was now explicit that only one train would normally work on the Maldon Junction - Maldon - Shelbourne line at any one time and no Staff Tickets were to be issued. Staff tickets could be used, but only if all trains operated between Maldon Junction and Maldon. If Staff Tickets were to be used and trains run to Shelbourne, Shelbourne Junction had to be opened as a staff station. Apart from this the instructions remained the same.
The instructions hadn't changed in the 1928 GA.
In the 1936 GA the instructions were further augmented to allow the Down Shelbourne Goods (with Staff) to follow the Up Castlemaine RM to the junction after a period of 10 minutes. The Goods (provided it had the Staff) did not have to stop to restore the junction points on the return from Shelbourne, but did so when it returned to Castlemaine.
Around 1950/1 the 8 ft square cabin at Shelbourne Junction was moved to Castlemaine for use by the Train Examiners. Its only contents, a telephone was relocated to a cabinet on a post. It was noted at this time that it was unlikely that Shelbourne Junction would again be opened as a staff station.
In the 1953 GA the instructions for the operation of the RM had been deleted, but otherwise the instructions were largely unchanged.
The home signals were removed on 4 March 1955. I would suspect this was after the formal withdrawal of the Temporary Staffs.