Traditionally, it was red & found at the end of a freight train
Traditionally, cabooses were painted red, and because every freight 
train had one, the image of the little red caboose at the end of the train... [DOC] [TLE] The Trains | Rochester Train Rides [PAR] Its unique tall hood on the short end earned it the nickname Hammerhead ... [DOC] [TLE] The colorful caboose | Trains Magazine [PAR] May 1, 2006 ... Once a fixture at the end of freight trains, the caboose played a critical role in ... 
Like the red schoolhouse and the red barn, the red caboose became an 
American icon.