jats:titleAbstract</jats:title> jats:pBase isolation is an established method of limiting the transmission of traffic-induced vibration into buildings. Despite this, the available design guidance is limited, and significant questions remain concerning how the vibration isolation performance may be optimised for a particular building. Recent research has sought to develop simplified models that enable the prediction of building vibration levels without resorting to complex numerical methods. This paper focuses on the phenomenon of soil-structure interaction (SSI) and considers the case of a multi-storey building founded on piles adjacent an underground railway. Some simplified models are compared against a comprehensive numerical model, with the aim of establishing the extent to which the various components of SSI influence the vibration transmission into the building and which should therefore be accounted for when predicting isolation performance.</jats:p>