Riding on the City of New Orleans

Before we embark upon the train and to test post, I thought it would appropriate to include a few words from Willie Nelson's The City of New Orleans. It is a song about the train we'll be riding.
We could subsitute "fifteen" for "twenty" and it would be perfect.

Riding on the City of New Orleans,
Illinois Central Monday morning rail
Fifteen cars and fifteen restless riders,
Three conductors and twenty-five sacks of mail.