Independent constraints on the ground motions experienced at Point Reyes station during the 1906 San Francisco earthquake are obtained by analyzing the dynamic response of a train that overturned during the earthquake. The train is modeled as a rigid rectangular block for this study. From this analysis, we conclude that the peak ground acceleration (PGA) and peak ground velocity (PGV) at Point Reyes station would have been at least and , respectively. This lower bound is then used to perform simple checks on the synthetic ground‐motion simulations of the 1906 San Francisco earthquake. It is also shown that the hypocenter of the earthquake should be located to the south of Point Reyes station for the overturning of the train to match an eyewitness description of the event.