Here are the dimensions I used for my 3d models for both Large and Small Countrylink boards

Large board
Length: (excluing post) 4m
Width: 0.15
Height: 1.25m

Countrylink Logo (Top board) board both large and small versions
Length: 1.18m
Width: 0.3m
Height: 1.12m

Post (Squared dimensions)
Width & Length: (Each post) 0.2m
Height: (Each post) 3.45m

Post frame large board
Length: 4m
Height: 0.1m
Width: 0.15m

Small board
Length: (excluding post) 2.32m
Width: 0.15m
Height: 1.25m

Post frame small board
Length: 2.32m
Height: 0.1m
Width: 0.15m

NOTE: That the main board and post frame cuts halfway into the post on each side
NOTES:
Post & post frames painted in light blue (Except Rydal station which was Red)
All boards painted in dark "Navy blue" I think can't remember if it was navy blue or dark blue
Canberra station top board was mainly dark blue in colour which featured both Countrylink blue and white logos
All Station names and line titles are in the Times New Roman font