Somewhere on the D&RG standard gauge would be my guess. I love these old pics of RR guys, in those early days of photography those guys had to pose for the camera for a while waiting for every condition to be close to perfect before the silver coated glass plate was exposed to the light of day and recorded the scene for us to wonder where it was and what were they doing there. Guys are guys though and it only takes a short study of the pic to see who's who in the group. The easiest one to peg is the fifth one from the right, ?somebodys dawg cruising for handouts. The guy dressed in dark on the left is in charge of the crew. And the guy up front recording the event on his tablet is the work crew bean counter keeping track of what this work stoppage photograph is costing the company. What kind of work? They don't really look like track workers. So to sum up my knowledge of that photo, I don't have a clue, but guessing is fun.
George