Built-up salt from recent weather conditions was responsible for a four-hour malfunction at a level crossing in Basford.
Traffic was delayed at the Davids Lane junction from 10.25am to 1.15pm on Friday, February 13, while Network Rail engineers found a fix to the problem.
Trams, trains and cars all cross the busy junction.
Nottingham City Transport said buses had no other route and services, such as the 68 and 69, were 20 minutes behind schedule.
A spokesman said: "It brought the whole area to a halt. The lights have been out of action most of the day.
"Traffic was queuing up both ways, up to Percy Street and Vernon Road. Our drivers just had to sit in it because there is no other way around.
"We have had to make some adjustments and put on extra services to get as many of our passengers to their destinations on time."
A Network Rail spokesman said: "The barriers were stuck in the lower position and our teams went out. The investigation revealed that the problem was a short circuit due to a build-up of salt in the line.
"Workers manually moved the barriers to allow traffic through safely."
