Smoking will be banned on all South West Trains' services from Sunday when the new timetable is introduced.
The move follows a partial ban, with smoking already forbidden on the majority of trains on the network. Head of customer service Andrew Fairbank said: "We felt the time was right to implement this total ban as new trains are gradually replacing older stock and we want to keep them in tip- top condition.
"This new policy brings us in to line with many other transport operators and is also in response to feedback we get from passengers who object to smoking on trains.
"We appreciate the co-operation of our passengers during the introduction of the ban, which is being brought in under the jurisdiction of the railway byelaws."
The ban has been communicated to passengers via posters, the company's website, announcements on trains and at stations.
A special information line has also been set up.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article