Interesting, so why is it not a bracket signal like all the others for a junction, can't be for lack of space or sighting surely?
Originaly all the direction signals were conventional brackets, as and when they were renewed straight posts with "Stacked Arms" were employed. Top arm always reads to the most Left-hand Route. Being a Goods Only Line, there was no requirment for a conventional bracket signals, straight posts and stacked arms are far cheaper, both in first cost and later maintainance. For what it's worth, and from my notes, the dates of the alterations are set out below. All signals were new in 1914, and as can be seen had a forty year life expectancy.
As an aside, my drawing though a copy of a so called "Offical" drawing shows KGD as it never existed.
WON 38, 1953 (5th appearance) says:
King George Dock: Bracket carrying:
No. 59 Coal Sidings No. 2 to Up H & B Mineral Home;
No. 58 Coal Sidings No. 2 to Up NE Mineral Home;
No. 57 Coal Sidings No. 2 to H & B Mineral Sidings
replaced by a straight post carrying Top Arm No. 59, Bottom Arm No. 58, and No. 57 Disc positioned immediately approach side of Nos. 58/59 signal post. All 3 yards nearer signal box. Upper quadrant.
I think 57G might have read through 52W and ?W (a single slip) onto the Down side of the Down (High Level H&B Mineral, which emerges at HDS as the H&B Sidings, connected to the Down Main by 10W and 11W, and protected by 20G.
Thursday 24 June 1954.
No25 Down N E Mineral to Coal Sidings No1.
No27 Down N E Mineral to Coal Sidings No2.
No32 Down N E Mineral to Coaling Berths.
Existing bracket renewed as a straight post signal with miniature arms.
No25 Top arm.
No27 Middle arm.
No32 Bottom arm.
11/12/1955 [M. N.]
18 & 20 signals renewed as 2 arm straight post
1956.
No12 Up H B Goods Starter.
No13 Up H B Goods Starter to Quay.
Existing bracket renewed as a straight post signal with a 3ft 6ins left-hand side bracket 2 yards further out. No13 now miniature arm.
Sunday 11 December 1956.
No18 Down N E to Down N E Goods Home.
No20 Down N E to Down N E Mineral Home
Existing bracket renewed as a straight post signal.
No18 Top arm.
No20 Bottom arm.