This is a 1951 linen postcard advertising the Monon Railroad which was known as "The Hoosier Line." A blue Monon logo is printed on the back of this postcard.
The railroad was nicknamed "Monon" because its four main routes converged in Monon, Indiana. From Monon, the main routes went to Chicago, Louisville, Indianapolis and Michigan City, Indiana. In 1956 "Monon" officially became the corporate title.
In 1959, passenger service between Chicago and Indianapolis was discontinued. Other passenger service was discontinued in 1967.
An interesting bit of trivia concerns Purdue University's "Boilermaker" nickname. The nickname originated when the 1891 Purdue football team included several boilermakers from the Monon Railroad Shops.