Construct Foundations for a New Rail Bridge using coffer dams and jump span bridges. The project involved constructing new bridge foundations while working under a live railway track, in a national park, in the middle of a wetland! To enable the construction of the new bridge foundations under the active mainline Johnston Construction designed and built coffer dams with some small jump span bridges over top. This allowed the train traffic to travel over the construction area. Piles were then driven by either temporarily removing the jumps spans or driving between the jump span ties. Following the installation of the piles, concrete pile caps were formed and poured in-place.