Simulation of traction and curving for passive steering hauling locomotives

Abstract

In a heavy haul train operations the ruling grades that set the tractive power requirements for train consists are often associated with tight curvatures. Past studies of passive or active bogie steering developments have been mostly directed towards high-speed rail applications or light rail and commuter rail applications and hence studies have focused on two axle bogies. Linked passive steering three axle locomotive bogies such as produced by General Motors Electric Motor Division for the SD70 class locomotive are in widespread use however, there are few publications on traction and curving, and few papers on linked passive steering bogies. This paper presents a simulation study three axle bogie locomotives on various curve radii with traction and variable rail friction conditions. Curving performance is assessed showing body linked radial bogies to have considerable advantages over axle linked bogies that are significantly better than yaw relaxation bogies at improving steering under traction. As traction adhesion approaches the rail friction coefficient steering performance of all bogies without forced steering deteriorates to the same levels as a rigid bogie.

Wagon instability in long trains

“…This modelling was incorporated into the train simulation process. Coupler angles were calculated using a technique developed by Simson [8] and utilised in many locomotive traction-steering studies [9,10]. This technique is easier to apply than the AAR [11] and has no significant error penalty unless used for very sharp curves (less than 0.1% at R = 100 m).…”

Simulation of active steering control for curving under traction in hauling locomotives

“…The choice of VAMPIRE software for use in this study was made based on its availability and ease of use. This is the same modelling package as used by the authors previously [10,11,16]. The limitations of the VAMPIRE software in this study are noted here.…”

“…The vehicle models used are the same as previously used by the authors [10,11,15], considering locomotives with two, three axial bogies. For each bogie design, the model uses the same bogie frame and wheelset dimensions and masses.…”

“…One example is the two axle DC283 bogie of Hokkaido Railway Company which has operated on a limited express train since 1997 [8]. Passive steering bogies have been shown to have deteriorated steering when operating traction forces are high [7,9,10]. Forced steered bogies maintain partial steering on curves as traction approaches creep saturation, while other passive bogie designs, such as self-steering and yaw relaxation bogies deteriorate to rigid bogie performance levels.…”

Simulation of traction curving for active yaw — force steered bogies in locomotives

“…Self-steering bogie designs developed by EMD and Clyde are reported to deteriorate with traction [5,6]. Simson and Cole [15] have shown that for passive steering designs when the wheel rail friction to adhesion ratio is low (e.g. adhesion approaches the maximum permitted by friction) performance deteriorates to that of a straight frame bogie.…”