After a study trip to the United States in 1916, Director Fredrik Kleven made the observation that wider vehicles were in use there. He brought the idea back to Trondheim, and the company made a policy to increase the distance between the tracks of a double line to allow wider cars to be put into service. This would allow four-abreast seating, and much higher capacity than with the existing stock. Five new Class 4 wide trams were delivered in 1930, after the Ila and Lademoen Lines had been rebuilt. Graakalbanen had taken trams of this width into use in 1924 along the Ila Line.