In the 1950s, with the final dominance of the automobile, ITC's passenger service became hopelessly unprofitable. This was even after IT had purchased three expensive electric multiple car streamlined train sets ("Streamliners") from St. Louis Car Company. These were capable of decent speeds on ITC's well-maintained open country roadbed, but had to negotiate tight streetcar-style curves in the numerous towns along the line; moreover, they suffered an abnormal number of failures. Worst of all, this new equipment generally failed to attract passengers, even on the St. Louis-Peoria runs which had no railroad or direct highway competition, despite having parlor-observation and dining facilities. On March 3, 1956, ITC's interurban passenger service ended, followed by its last passenger service, the St. Louis-Granite City suburban cars, in 1958.