Supply crate at trainstation is in the main building, up against the wall.
There isn't a resupply crate at the Farmhouse I am aware of.
At the airfiled, it's in the building close to the flag, up the ladder, where the FG41 is.
At the church, I believe it's in one of the open buildings across the park from the Church, the house that faces the AT gun squarely, I believe.