Yes it is a religious thing, though it is more about covering the head not the turban. This is kind of half and half depending on how orthodox the sikh is. So many Sikhs will wear anything on their head, helmet, hat etc.
Yes, I was thinking of that powering cogwheel. But I realize, the little raised wheel there is probably the back of the tank, eh. Not the front driving wheel, which is probably a cogwheel out of frame.
But yeah, the wheel with the cogs isn't called a "cog", it's a "cogwheel", with "cogs". The cogs are the little "teeth". 👍