The main line was opened to Westville Road (Route 421), just east of the Monon Railroad bridge, in June 1908. To generate some revenue, an amusement park called "Air Line Park" was set up west of the Pere Marquette Railroad bridge. This proved very successful, and thousands visited on weekends when a ten-cent shuttle service from La Porte was provided. This was to be the only public service on the main line for the next three years, running from La Porte to Westville Road and back.