12 Vehicle suspension systems and components, namely, hydro pneumatic suspension units comprised of a high-pressure nitrogen gas spring an integral oil damper to form the base-strut, and a damping kit, pneumatic spring suspension units comprised of a high-pressure nitrogen gas spring and an integral oil damper, pneumatic spring and damper units comprised of a strut and a damping kit, rotary dampers, dampers, springs, controllable springs and dampers, real-time controllable springs and dampers, suspension controllers in the nature of controllers to interpret sensor signals used to control damping valves used in active damping upgrade kits or to control motors used to generate positive force used in fully active upgrade kits, controllers to control the pump and manifold system used to move oil to and from a reservoir and the strut; vehicle suspension systems and components for heavy duty road and rail vehicles and for military vehicles, namely, hydro pneumatic suspension units comprised of a high-pressure nitrogen gas spring and an integral oil damper to form the base strut and a damping kit, rotary dampers, dampers, springs, controllable springs and dampers, real-time springs and dampers, running gear comprised of running gear components for tracked vehicles, namely, road arms, bump stops, support rollers, idler arms and final drives, track tensioners, top rollers as parts of struts, suspension controllers in the nature of controllers to control the pump and manifold system used to move oil to and from a reservoir and the strut; replacement parts and fittings therefor for the aforesaid goods