IOWA CITY — About midway between Iowa City and West Branch on Lower West Branch Road SE, just south of Interstate 80, a crew of bridge contractors carefully lowered three large sections of steel and wood into place.Spanning Wapsinonoc Creek, the bridge is not a traditional structure of timber, steel or concrete, but rather three retired railcars placed side-by-side.Recycling beds of railcars into a bridge is not new to Iowa, but Ed Bartels, assistant Johnson County engineer, said it’s a brand-new venture for the county.“For us, this is definitely a unique project.