Trains between Manchester and Tameside are being forced to slow down due to the hot weather.
Rail bosses activated the 'extreme weather response' through fears the high temperatures could cause the tracks to bend - or in serious cases buckle.
It comes as temperatures in the region hit 30c.
According to Network Rail , the steel rails absorb heat easily and be around 20c hotter than the surrounding air temperatures.
It means that on a day like today (Tuesday), the tracks could rise to around 50c.
The reduce the risk of damage, trains between Manchester Piccadilly and Stalybridge are running slower than normal, with potential delays of around 15 minutes.
A spokesman for Network Rail said: "Keeping passengers moving safely is always our top priority.
"When steel rails get too hot they can bend and buckle.
"To avoid the reduce the risk of buckling we must slow down trains. It may mean some journeys take longer.
"We advise passengers to check before they travel during the hot weather."
