Equations are summarized to calculate deflections and axial stresses due to torsion in channel sections used for truck frame rails. Symmetric channel sections are treated first and calculations are made for a specific case. These results are compared with strain gage data from tests conducted by Lewis F. McNitt. Computer modeling of truck frame rails is discussed and results are presented and compared with the McNitt test frame. The special case of unsymmetric channel sections is also discussed and results are presented from a computer model of a truck frame.