This paper describes railway vehicle vibration mechanism whereby offset suspension elements position affect bogieframe vibration response. Primary suspension elements are often set on offset position from center of axlebox, so we hypothesized that offset primary damper position trigger axlebox rotation around axlebox bearing, which play pivotal role in inducing bogie-frame pitching via coil spring. To address this hypothesis, we conducted whole vehicle vibration analysis, focusing on axlebox damper vertical damping force and coil spring horizontal force applied on the offset position from center of axlebox. Analysis results showed that the mechanisms are suggested to involve bogie-frame vibration response mediated by axlebox rotation as well as coil spring horizontal force.