What an interesting picture.
The sign indicates it’s an urban gas company, selling off its lower grade coke byproduct for domestic heating.
Some sort of celebration by the gas company, I think:
A fellow with a piano accordian in the front of the wagon. The wagon decorated with paper mache balls. All the workers wearing cardboard top-hats - all bosses for the day.
And the fellow in a real (black) top-hat - a real boss, no doubt - what is he doing? Could it have something to do with the occasion? He appears to be holding a heavy-ish cylinder, his right hand on what looks like a thermos flask, with his left hand holding a thinner extension or projection from the cylinder - if it’s his hand I’m seeing. He appears to be pouring something from the cylinder into what looks like a jar, cupped in the hands of the man next to him.
Or a soda syphon - but it doesn’t really look like one.
Or - and I risk an anachronism here, because I don’t really have a clue whether it’s feasible for back then - could he be inflating a balloon from a portable coal gas cylinder? Could they actually be celebrating some sort of innovation like small portable gas cylinders?
Perhaps, odbsmith, you can see more clearly in the original photo what they are really doing.
Peter