Sometimes you can’t even take a painted train carriage into the open air to photograph it, for fear of zoom lenses and other nosy parkers.
Not only must you stay on the alert for enemy spies and press leaks, there are individuals hounding stations with a lust for trains and all they stand for.
Simon Ingleton at CGI discovered this while testing new looks for Connex Rail, which was keen to make a splash with its newly franchised line.
On its debut outings, the train was repeatedly pursued by a guy in an anorak following in his car, furiously photographing the carriages from all angles.
Was he a rival employee, a reporter from Railway Gazette, or even another designer?
No, this individual had spent the last several years constructing a model replica of this exact train. He had, in fact, just finished painting his pride and joy when he got wind of the new livery. Poor chap.
Ingleton is perhaps a little less tolerant. “It shows the level of madness out there,” he says.