The Sensor Platform (SP) Framework was a system engineering project conducted in conjunction with the Association of American Railroads-funded development of automated train operation (ATO) system requirements. The SP is a device that monitors the external environment in front of the train for potential hazards and interfaces with other locomotive onboard (OB) systems to obtain operational data, archive data, and report hazards detected. The SP Framework project supported the ongoing FRA- and AAR-funded ATO development effort by developing an interoperable SP reference model and beginning the decomposition of the existing SP requirements into the services defined by the SP reference model. The SP Framework project produced a completed draft SP reference model and started progress on revised SP-reference-model based requirements documentation.