Examination of an electron beam-welded torsion bar on the APT-H4X bogie (IM-FM-042)

The centre portion of the anti-roll bar on the APT-H4X bogie experiences very high torsional forces in service, and it has therefore been necessary to use a high-strength steel (BS970 826M31, formerly En25) for this region. However, the design of the bar is such that this steel could not be...