The Southern train company is to impose a ban on e-cigarette smoking.
The rail firm will, from July 26, join a number of other rail firms in banning e-cigarettes across all of its services and at stations.
Southern's services include the Gatwick Express. Other companies within the Govia Thameslink Railway franchise - Thameslink and Great Northern - already have e-cigarette bans, as has Transport for London.
Chiltern Railways has had a ban in place for some time, while First Great Western introduced a ban for passengers on trains and at stations, as well as for staff at depots, in April 2014.
The CrossCountry company said it did not have a ban as such but passengers were asked not to use e-cigarettes
E-cigarette smoking has been banned on ScotRail since June 2013, while the practice has been outlawed on South West Trains and East Midlands Trains for some time.