The present disclosure provides elbow assemblies for ramp and platform assemblies, and ramp and platform assemblies. The elbow assembly includes a first elbow sub-part that is configured to nest within a second elbow sub-part. The elbow assembly includes useful features, including structure that enables direct connection either to a tubular support member or a flat portion of a support member, and structure that provides a smooth transition between the first elbow sub-part and the second elbow sub-part at any angle within the range of motion.