The Alaska Railroad Corporation is planning and designing the Northern Rail Extension Project to extend from a location on the Eielson Branch near North Pole, Alaska to Delta Junction, Alaska, a distance of approximately 80 miles. The alignment crosses the Tanana River near Salcha, Alaska. This railroad crossing is known as the Tanana River Bridge Project. The Tanana River is a large, glacially-fed, braided river capable of transporting large amounts of woody debris, silt, sand and gravel. At the location of the planned crossing, the Tanana River is approximately 0.9 miles (1.44 km) in width. Current design for the bridge support structure calls for 12-ft diameter piers constructed at 165 ft centers. While local pier scour is to be expected, the relatively short span between piers has raised concern regarding potential erosion and scour of the foundation due to the pronounced lateral contraction of the flow. Large woody debris can also contribute to bridge scour in the braided Tanana River. Through an agreement with Hanson Professional Services, Inc., the engineering firm responsible for the design of the bridge, Professor Garcia’s group is conducting a movable-bed model testing of potential bridge scour in the Ven Te Chow Hydrosystems Laboratory. The 1:50 Froude scale physical model uses crushed walnut shells to model the sediment of the Tanana River. Garci’s group will assess how much erosion might take place during floods at the bridge piers due local scour, flow contraction and debris accumulation. Hanson water resources engineers will use this information to finalize the design of the railroad bridge foundation.