The Tiffany patent calls for a ice bin running the lenght of the car, and mentions the roof as one possible location (not the only possible location) so instead of end ice bunkers these cars commonly have trays along the underside of the roof.
At least one ad cut used by Tiffany had a clearstory the length of the car, so the three raised ice hatches is consistent with the patent.
The Tiffany patent was widely used by railroads.
Randy
Randy Hees
Director, Nevada State Railroad Museum, Boulder City, retired
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