Three axle locomotive bogie steering, simulation of powered curving performance passive and active steering bogies

It has been shown that active steering control can improve steering performance in two axle bogies whilst also improving high speed train stability. In freight operations passive steering three axle bogies have been produced in large numbers for reported benefits including improved adhesion performance and reduced wheel wear. However, passive steering bogie designs have been shown to perform similarly to straight rigid frame bogies under high traction forces due to the loss of longitudinal creep forces. These factors have not been modelled for hauling locomotives and published in public domain though commercial testing by locomotive manufacturers has occurred. A gap therefore exists in the knowledge of steering bogie performance in freight locomotive operations particularly for three axle bogies. The following thesis explored traction curving operations for hauling locomotives considering, and in particular, the effect of high adhesion levels, rail-wheel contact friction and lateral components of coupler forces. Both passive and active designs were analysed and new designs were proposed. Methods of active control and data measurement were also compared and discussed. The following three axle bogies were evaluated and compared. • Bogies with passive steering: Rigid, yaw relaxation, self steering, forced steering. • Bogies with actively controlled designs: Actuated Wheelset Yaw (AWY) bogies with creep force control; steering angle precedence control; yaw angle precedence control. • Bogies with new designs developed as part of this thesis: Actuated Yaw Force Steered (AY-FS) bogies with creep force control; precedence control; and curve estimation control; Actuated Yaw Variable Steering (AY-VS) bogies with precedence control and curve estimation control. It has been shown that active steering control can improve steering performance in two axle bogies whilst also improving high speed train stability. In freight operations passive steering three axle bogies have been produced in large numbers for reported benefits including improved adhesion performance and reduced wheel wear. However, passive steering bogie designs have been shown to perform similarly to straight rigid frame bogies under high traction forces due to the loss of longitudinal creep forces. These factors have not been modelled for hauling locomotives and published in public domain though commercial testing by locomotive manufacturers has occurred. A gap therefore exists in the knowledge of steering bogie performance in freight locomotive operations particularly for three axle bogies. The following thesis explored traction curving operations for hauling locomotives considering, and in particular, the effect of high adhesion levels, rail-wheel contact friction and lateral components of coupler forces. Both passive and active designs were analysed and new designs were proposed. Methods of active control and data measurement were also compared and discussed. The following three axle bogies were evaluated and compared. • Bogies with passive steering: Rigid, yaw relaxation, self steering, forced steering. • Bogies with actively controlled designs: Actuated Wheelset Yaw (AWY) bogies with creep force control; steering angle precedence control; yaw angle precedence control. • Bogies with new designs developed as part of this thesis: Actuated Yaw Force Steered (AY-FS) bogies with creep force control; precedence control; and curve estimation control; Actuated Yaw Variable Steering (AY-VS) bogies with precedence control and curve estimation control. Active bogie designs were also analysed with idealised control systems to provide a datum for comparison.