Thanks. So I took a tour with Google satellite maps and topography and from what I can tell from the areas I looked at along the Vietnam Veterans Memorial Hwy (I-84) there is mostly single track. Some places are double tracked but these may be sidings not main line track. Interestingly looking at the north side of the Columbia along the Lewis & Clark highway I believe I see BNSF trackage, also single track. For UP to increase the double track areas there would need to be tunnels and bridges widened.