graakalbanen was on 1 january 1972 merged with trondheim sporvei to form trondheim trafikkselskap. this would allow the service to run through the city centre, and connect with other routes. from 28 january 1978, the line was numbered as 1/5 and went on the route voldsminde–ilevolden–munkvoll–lian, replacing former line 1. the terminus at st. olavs gate was closed, and passengers were no longer offered a heated waiting room.