There was another picture, obviously not part of the set, that shows earth moving activities. It appears that they are building an earthen dam.
Come the 1890's, the Willier Contracting Co. was faced with two problems, first, there was a severe economic downturn in the US with little work available, and second, to add to it, the peak of railroad construction was long past.
Earth-moving is an integral part of building a railroad bed so it would be well within their capabilities to move earth for a dam. From our information, they also did work in Jamaica on this swing south.
There are two links. The first is the dam site picture from this site (below). For the second, to show off 22 pictures I made use of a free photo site. When you go there just follow their menus. It will be the last item on my main menu so when you go there you don't have to return to FAMILYROOM.