Leaves and bomb scare delay trains.
A spokesman for Network Rail confirmed there were problems due to the railhead (part of the track) being wet and slippery, meaning it was difficult for the wheels of trains to gain traction.
And in Aber, near Caerphilly, Post Office workers thought they had found a suspicious package and called in police officers.
On the South Wales network there were more than 23 incidents of delays, including the first train down from Rhymney, and the 6.33am service between Penarth and Bargoed lost 37 minutes of its journey due to "exceptional railhead conditions" from Heath to Llanishen.
A spokeswoman from Gwent Police confirmed that Royal Mail staff in Aber called them with a suspicious package alert. Aber railway station was sealed off while checks were carried out. Trains were stopped from running through the station for approximately 15 minutes.
She said: "We were called at approximately 8am this morning as the Royal Mail offices thought a package was suspicious.
"A cordon was put in place and trains were put on temporary stop as a precaution, the railway runs directly behind the building, while an investigation was carried out.
"We consulted with the Explosives Ordnance Disposal and, as a result of inquiries made by police officers, the package was examined and deemed safe."