Pictures taken on a tram on the Bury line last night show a crowded carriage with passengers unable to socially distance.
The images sent to the Manchester Evening News were taken on a Metrolink service approaching Abraham Moss at around 8pm on Monday.
They show a carriage packed full of people.
Passengers appear to be unable to keep a safe distance from each other and are standing close together.
The seats on the carriage appear to be full with many passengers also having to stand.
Most passengers appear to be wearing face coverings in the pictures.
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Transport bosses said the trams became crowded after a points failure temporarily delayed some services on the Bury line.
They said this led to ‘increased passenger loading for a short time’ but was an ‘isolated incident’.
TfGM apologised to anyone ‘who experienced a more crowded journey than usual’.
In a statement, TfGM’s Head of Metrolink, Danny Vaughan, said: “Passenger safety is our top priority, which is why recently introduced a raft of new safety measures, including an extra 500 hours of cleaning each week, new hand sanitiser dispensers at stops and our new ‘trambassador’ customer safety representatives.
“Unfortunately, a points failure at around 6pm yesterday temporarily delayed some services running between Bury and Whitefield.
“Full service resumed at 7pm, but the delays and the 20-minute evening frequency temporarily increased passenger loading for a short time.
“I’d like to apologise to anyone who experienced a more crowded journey than usual but would reassure passengers that this was an isolated incident related to the disruption.
“We were running all the trams available, including as many doubles as possible, across the network yesterday and will continue to target capacity where it is needed most.
“The first of our 27 new trams is also set to go into service in the next few days, with more to follow in the coming months.
“This year, we’ve also run more than 40 days of action to hand out thousands of free face coverings and speak to passengers about the importance of protecting themselves and others by wearing them and following all other safer travel rules and guidance.”