Isambard Kingdom Brunel FRS 9 April 1806 – 15 September 1859, was an English mechanical and civil engineer who is considered "one of the most ingenious and prolific figures in engineering history", "one of the 19th-century engineering giants", and "one of the greatest figures of the Industrial Revolution, [who] changed the face of the English landscape with his groundbreaking designs and ingenious constructions". https://en.wikipedia.org/wiki/Isambard_Kingdom_Brunel
What is less well known is that his hat (and that of other engineers), actually was a chimney for a steam-operated mechanism. This started a fashion for 'stove-pipe' hats but for most people these were just hats and did not have any dangerous steam-powered mechanism.
This is a redacted photograph to hide the smoke and steam from Brunel's hat.
This is the original uncensored photograph.
Why would the government of the day want to suppress knowledge of these 'engineers hats' from the general populace?
Remember that using the technology of the day, most of the public would only have seen pictures in still photographs.
Note for those who are voting to close on the basis this is not world-building
Yes it is. Although I use Brunel as an exemplar, in the world I propose almost all engineers wear these steam hats. Their existence is essential to the development of technology in this world.