A universal boxcar is provided with exterior metal surfaces and load carrying capabilities of a conventional uninsulated boxcar and thermal transfer ratings of an insulated boxcar. The boxcar may be formed with interior dimensions corresponding generally with interior dimensions of an uninsulated boxcar without high cost, high performance insulation. The boxcar may include a double side doors slidably mounted on the exterior of each sidewall assemble. A load restraint system may be provided with improved load carrying capabilities and performance characteristics. The load restraint system may have increased load carrying capacity, increased service life, and reduced maintenance costs. All or portions of the load restraint system may be used in uninsulated boxcars or temperature controlled railway cars.