Whirly Wheels?

This photo was taken to show something else, but on the tender wheels on the right you can see the cast in pattern on the back plate of the wheel.  Many real cast iron railroad wheels had these stiffing ribs cast into them. Lionel reproduced this detail on some of there wheels made in 1945 and/or 1946.  Some of the scale prewar wheels made between 1937 and 1940 also had this detail.  I believe these wheels are zinc die cast.  This detail was dropped when they went to sintered steel wheels.  

Thanks for the info! I had seen this reference on a few auctions and couldn't search anything up.

Does this apply to locos? or just rolling stock?

Just car wheels.  On real railroads they would be on just freight cars. 

This is how it looked on a real railroad car. 

Tom