Not much seems to be known about C&O observation cars.  They did have several business cars, #1-7 and 25-29.
  
   
    | observation-business car c&o 3_art |  | 
   
    | observation-business car c&o 3_art / fec_obs_art_512.tga | 1.0 MB | 
   
    | observation-business car c&o 3_art / fec_obs_art_icon.tga | 32.0 kB | 
   
    | observation-business car c&o 3_art / observation-business car c&o 3_art_512.texture.txt | 79 B | 
   
    | observation-business car c&o 3_art / observation-business car c&o 3_art_icon.texture.txt | 81 B | 
   
    | observation-business car c&o 3_body |  | 
   
    | observation-business car c&o 3_body / $screenshot$.jpg | 5.6 kB | 
   
    | observation-business car c&o 3_body / brownmetal.texture.txt | 33 B | 
   
    | observation-business car c&o 3_body / brownmetal.tga | 12.0 kB | 
   
    | observation-business car c&o 3_body / brownmetal2.texture.txt | 34 B | 
   
    | observation-business car c&o 3_body / brownmetal2.tga | 12.0 kB | 
   
    | observation-business car c&o 3_body / burgundy.texture.txt | 31 B | 
   
    | observation-business car c&o 3_body / burgundy.tga | 3.0 kB | 
   
    | observation-business car c&o 3_body / elevation-elevation.texture.txt | 34 B | 
   
    | observation-business car c&o 3_body / elevation.texture.txt | 32 B | 
   
    | observation-business car c&o 3_body / elevation.tga | 2.0 MB | 
   
    | observation-business car c&o 3_body / gold.texture.txt | 27 B | 
   
    | observation-business car c&o 3_body / gold.tga | 3.0 kB | 
   
    | observation-business car c&o 3_body / light.texture.txt | 28 B | 
   
    | observation-business car c&o 3_body / light.tga | 3.0 kB | 
   
    | observation-business car c&o 3_body / logo.texture.txt | 27 B | 
   
    | observation-business car c&o 3_body / logo.tga | 16.0 kB | 
   
    | observation-business car c&o 3_body / observation-business car c&o 3_body.im | 277.6 kB | 
   
    | observation-business car c&o 3_body / rail-rail.texture.txt | 43 B | 
   
    | observation-business car c&o 3_body / rail.bmp | 17.1 kB | 
   
    | observation-business car c&o 3_body / rail.tga | 48.0 kB | 
   
    | observation-business car c&o 3_body / roof1.texture.txt | 28 B | 
   
    | observation-business car c&o 3_body / roof1.tga | 12.0 kB | 
   
    | observation-business car c&o 3_body / toolbox.texture.txt | 30 B | 
   
    | observation-business car c&o 3_body / toolbox.tga | 24.0 kB | 
   
    | observation-business car c&o 3_body / yellow.texture.txt | 29 B | 
   
    | observation-business car c&o 3_body / yellow.tga | 3.0 kB | 
   
    | observation-business car c&o 3_shadow |  | 
   
    | observation-business car c&o 3_shadow / black.texture.txt | 28 B | 
   
    | observation-business car c&o 3_shadow / black.tga | 786 B | 
   
    | observation-business car c&o 3_shadow / observation-business car c&o 3_shadow.im | 4.9 kB | 
   
    | Общий объём файлов: | 3.5 MB |