Internally, the walls are painted plaster, and original joinery is generally extant. Floor finishes are generally modern (either tiled or linoleum). Ceilings are modern plasterboard with cornices, although some original boarded ceilings remain. The station masters office features a timber mantelpiece and a blocked fireplace. External: The station building on Platform 2 (Down Platform) is very similar to the building on Platform 1, being of brick construction with a corrugated iron gabled roof, and replaced an earlier building on Platform 2. The roof features bargeboards (not scrolled) and timber finials. There is a central double breasted chimney stack with corbelled brick string course. A small awning (not the whole length of the building) is supported on arching cast iron brackets and features timber valances. All external original joinery is still extant, including double hung sash windows. The eastern end of the building features an attached brick toilet block with gabled roof (slightly lower than the station building), also with bargeboards and finial. The toilet block wall presents three recessed lower bays and six sets of air vents to the platform side, and is entered by an arched brick opening. A small brick toilet block exists at the eastern end of Platform 1. The building has a tiled floor and corrugated iron gabled roof, and is likely to be the most recent building to have been constructed on the platforms at Hamilton railway station. A small store room is located at the Newcastle (eastern) end of the Platform 1 building. It is unsure when the structure was built, but it features in a c.1900 photograph of the station. The building is square in plan and is of brick construction with a corrugated iron hipped roof. Access is by a door in the eastern wall, while the northern wall features a small window. A storage box for a wheelchair ramp is attached to the northern wall. Hamilton Junction signal box is located adjacent to the main Sydney to Newcastle railway line and Beaumont Street at the Sydney-end of Hamilton railway station. The signal box is a two-storey Type E2 structure. The ground floor is of brick construction and features four six pane arched windows on the northern (railway line) elevation. The southern (Esplanade) elevation is of brick construction to roof height with two timber framed sash windows, while the northern wall is brick to sill height, above which sliding timber-framed six pane glazed windows extend around the perimeter.