A large number of bricks crashed onto a railway station platform when a roof and wall collapsed.
Cheshire Fire and Rescue said the incident at Northwich station happened at 10.29am on Tuesday.
No-one was injured, but rail services were severely disrupted as debris blocked the adjacent line.
Network Rail’s infrastructure delivery manager Allan Gibbs-Monaghan said: “We’re sorry to passengers affected by the partial building collapse at Northwich station today.
“Fortunately, no-one has been injured. It’s too early to say what caused this, but investigations are under way.
“Fire crews have now let the scene but the station remains closed.”
Train operator Northern, which manages the station, said journey times would be extended by up to 40 minutes.
Passengers are being advised to check National Rail Enquiries before they travel.