Original 1957 Dairy Queen Miniature Store Coin Bank DQ 17th Birthday. There is some glue residue on the bottom where it was attached to a train display.
 From the 1957 DQ promotion: 
"It’s our way of saying thank you for coming to our 17th birthday party! An attractive Coin Bank, a unique toy train accessory or mantle decoration. This offer is good during party days only beginning June 18 at every store displaying our birthday poster so make it a date make it a party at Dairy Queen."