Answer by the EIA:
"Some ethanol plants store their product in railcars onsite at the facility, and denture the ethanol as it sits in the rail cars. The instructions quoted below ask companies to include any fuel ethanol in those railcars as they sit at the plant. However, once those railcars leave the production plant, those stocks are considered to be “in-transit” to a terminal, and are to be included in the inventory of that receiving terminal/facility. Railroads do not report to us."