Dynamics Analysis And Safety Design Of Locomotive With Lateral Coupling Device

3B₀ locomotive has advantages over traditional 2C₀ locomotive in small radius curve negotiation and wheel flange reduction, and it also has advantages over locomotive with radial bogies in costs and technique difficulties. So it is used broadly on those lines with low-grade, high slope and small radius curves. To meet the need of traffic capacity and passing speed for mountain railway lines, Italy, Japan, Jugoslavia, France, Switzerland, Britain, Sweden etc., designed and manufactured various 3B₀ locomotives. However, the middle bogie of 3B₀ does not share the centrifugal force of the car body on curves, which results in increasing the lateral force and the derailment coefficient of the front guide wheel. The objective of the paper is to research how to reduce that share and decrease the derailment coefficient, angle of attack and wheel flange wear of the front guide wheel.Lateral elastic coupling device is one of the best approaches to achieve the objective. The rear end of front bogie moves to outer rail and the front end of rear bogie moves to inner rail, which reduces the attack angles and guidance forces for both guide wheels by the bogie's structure other than lubricating devices. Establishing the multi-body dynamic model for both locomotives (with or without torsion bar lateral coupling device), the paper calculates and compares kinds of dynamics index. It shows that the device not only has not effect on the running quality of straight lines but also to some extent improves the lateral ride index; for the angle of attack and lateral force reduce greatly, the derailment coefficient and friction power of gudiance wheel decrease with obvious effect of wear-reducing.For locomotive the safety is very critical. It is also important to guarantee the free clearance, prevent the spring from deadlocking and avoid device falling off etc. The general design principles for the device are: it does not worsen the ride index on straight lines; wear reduction should be achieved to some extent and some attentions should be paid to the derailment coefficient and lateral force for the second wheelset; and the device should have high safety by guaranteeing that no blocking, falling off, cracking and so on take place.As one of the best ways of reducing wheel flange wear further and improving the locomotive operation safety, 3B₀ locomotive with lateral coupling device can meet the requirement of the mountain railways with numerous small radius curves in China with wide prospect of application.