In the past few months several model railway layouts in Railway Modeller and the Hornby Magazine have had gantry-mounted signal boxes. A few of these seem to have been existing models with brick bases simply plonked down onto a girder gantry above the tracks.
Now none of my books on the prototype or on modelling signal boxes shows a brick-based box on a gantry - they are always wood, whether of one or two floors. And to be honest I can't imagine the railways erecting a brick-based box on a gantry because of the much greater weight of the bricks compared to wood needing a much stronger structure!
So were there any examples of brick based boxes on gantries in real life?