Here’s a list- still in progress- of locations of Washington’s Blue Bell Hamburgers/ Waffle Shop chain.
http://www.loc.gov/pictures/search/?q=%22waffle%20shop%22&co=thc

Blue Bell System
902 F Street NW (office in 1941)
1790 Columbia Road
4416 Connecticut Avenue NW
502 9th Street NW
1402 Park Road NW
1011 Pennsylvania Ave. NW
4300 Connecticut Avenue NW
1201 Gallatin St. NW (Office in 1936)
721 13th St. NW
1421 I street NW
522 10th NW
619 Pennsylvania Ave. NW

Cameo Waffle Shop – 800 19th Street NW
Carl’s Waffle Shop – 1234 Wisconsin Ave. NW
Frank’s Waffle Shop – 1633 17th Street NW
Sheridan’s Waffle Shop – 6214 Georgia Avenue NW
The Waffle Shop – 241 4th Street NW
Waffle Shop offices- 1419 I Street NW
Walnick’s Waffle Shop – 1143 Connecticut Avenue NW
Waffle Shop – 425 12th Street NW
The Waffle Shop – 522 10th Street NW
3864 Mount Vernon Ave – Alexandria, VA
Lincoln’s Waffle Shop – 504 10th Street NW
Waffle Shop – 4539 Wisconsin Ave NW photo