More than 30 Gatwick Express train services between London and the airport are being cancelled daily because of the possibility of leaves on the line.
The company said it was “inline with the rest of the industry”. But Southern and Thameslink who run on the same track, is making no changes its services.
The 33 cancellations affect weekday services between 05:30 and 22:30 and will be in force until 8 December.
There are also no overnight trains during the period.
On its website, the company said that the changes would help to reduce congestion and reactionary delays to Gatwick Express and other services on the Brighton Mainline.
Southern and Thameslink services will continue to run throughout the night.