An arm on the top of each box rotates a shaft when pushed or pulled. The shaft extends to the bottom of the box and moves a flap over a hole to allow or prevent the sand descending through the hole to the track.
The two front and the near-side rear boxes are all operated by one lever, the one to the left of the reverser lever. Oddly, the off-side rear box is operated by another lever, the one to the right of the reverser lever, via a vertical shaft.
|LH lever operates 3 boxes via a cross shaft behind the boiler and below the coal bunker.|
RH lever operates the offside rear.
The sandboxes are heavy castings; one box's mechanism in particular had seized due to rust combined with sand over a long period.
|Flap seized over the hole (the fluid is diesel to attempt to free it)|
|One attempt to free the mechanism freed only the end of the flap!|
|Sandbox "remodelling" begins!|