Landslip disrupts train services between Swindon and Bristol
Train services between London Paddington and Cardiff Central have been disrupted following a landslip between Swindon and Bristol Parkway.
The disruption on First Great Western's eastbound service follows a landslip near the Chipping Sodbury tunnel.
A National Rail spokesman said trains were subject to a speed restriction and may be "cancelled or delayed by up to 15 minutes at short notice".
Overnight frost and recent wet weather has been blamed for the landslip.
A Network Rail spokesman said about 25 tonnes of material and several small trees had been deposited on the line.
"In order to raise the speed restriction of 5mph past the slip, overnight work will be required," he said.
"But hopefully by the morning it will be up to 40mph."