People travelling on South West Trains (SWT) between Brentford and Hounslow can expect major delays on the line.
Engineers are carrying out urgent repair works out on the damaged railway line following an earlier incident on Thursday (July 14), which has led to part of the Hounslow-bound line being blocked.
As a result a number of services have been cancelled, delayed or are on diversion via Richmond.
SWT trains has reported the disruption will affect customers until 4pm.
A statement from SWT said: "Damage caused to the railway line by an unknown incident this morning means that engineers need to make urgent repairs to the railway line.
"This means that trains are unable to run between Syon Lane and Hounslow in the Hounslow-bound direction.
"We're investigating the cause of the incident at this time.
"We're sorry for the continued disruption to your journeys this morning."
SWT tickets can be used on London Buses between Barnes and Hounslow via Brentford.
There were SWT delays on Wednesday (July 13) after a fire near Clapham Junction station led to cancellations and delays into London Victoria.
Watch the dramatic footage of the huge fire
If you have been delayed by over an hour visit Refunds and Compensation.
