A rail vehicle includes a truck having wheels for engaging a railroad track, a bolster supported by the truck, and a tank supported by the bolster for storing a lading. A measurement system measures the level of the lading within the tank and includes gauges and a controller. The gauges are disposed at selected points on the bolster for sensing at least one of lateral and longitudinal localized displacement experienced by the bolster during motion of the rail vehicle. The controller calculates the level of the lading within the tank and compensates for changes in the level of the lading during motion of the rail vehicle in response to signals generated by the gauges.

A container includes a bottom surface, at least one side surface, and a single-axis distance sensor. The at least one side surface surrounds the bottom surface to form a closed shape. The single-axis distance sensor is configured to project a line light ray within a horizontal plane, at which the single-axis distance sensor is disposed, to receive and sense a reflected line light ray from substance in a space formed by the bottom surface and the at least one side surface.