In train collisions there are two distinct objectives to improve passenger safety:
elimination of vehicle over-riding or climb over.
prevention of uncontrolled structural collapse.
Both are achieved by managing the impact energy absorption and dissipation. Rail vehicles are now designed with controllable deformation characteristics and higher energy absorption characteristics in couplers as well as anti climbing features.
Without anti climbers one vehicle will over ride another in a serious accident. Oleo anti climbers contribute to the 'crash worthiness' of rail vehicles in two ways:
By absorbing impact energy as collision forces rise following coupler overload. This can be by incorporating a gas hydraulic unit and /or a deforming tube in one or more stages.
By locking vehicles together during the early part of the collision; controlling vertical movement and helping to direct forces longitudinally.
The anti climber contact faces lock together prior to any vehicle structural deformation and minimise the tendency of vehicles to climb or override.
Oleo were involved in the development of anti climbers working in conjunction with British Rail Research in the 1990's when it was established that end on collisions of railroad vehicles presented the greatest hazards to passengers and that most fatalities happened at speeds of less than 60km/h, where successful prevention of over riding and energy management are possible. Extensive full size vehicle impacts were undertaken and the results can be seen in a film entitled "Oleo Crash Energy Management".
The Oleo deformation tube has been specifically designed to limit vertical movement even in offset impacts, and promotes a controlled longitudinal stroke. Oleo anti climbers have benefited from extensive dynamic testing as static compression tests do not realistically reflect the performance characteristics during a collision. Oleo recommends that the strength of the engaged anti climbers should be significantly more than 50% of the specified weight of a fully laden vehicle.
These units are customised to meet the geometry and specific parameters of a train and Oleo has implemented many successful projects.
Oleo anti climbers are available as standard designs or to a specific requirement.