Instructions: In this task, you are given an article. Your task is to summarize the article in a sentence.
Input: The deal centres on the firm's dispute with workers over a plan to introduce driver-only operated (DOO) trains.
Drivers' union Aslef members voted on a second deal after members rejected initial proposals in February.
The firm remains in a year-long dispute on the issue with the RMT union, which represents guards on Southern trains.
Aslef's ballot result is due is due to be announced at 13:00 BST.
In February, its members threw out the initial deal with Southern by a majority of 54.1% after 11 days of talks between the rail operator and the union.
The firm's plan for guards to become on-board supervisors, leaving drivers with the responsibility of opening and closing carriage doors was initially opposed by the RMT union, last April.
Leader Mick Cash said the move reduced the safety of passengers and staff on board trains and urged Southern Rail to put "safety before profits".
Industrial action began in April 2016, and Aslef members joined the picket in December.
Up to 2,000 RMT members on Southern rail, Merseyrail and Northern rail walked out earlier this month and the next strike is planned for Grand National day, 8 April.
Merseyrail, which plans to introduce a new fleet of 52 (DOO) trains from 2020, has created a contingency timetable as fewer trains will be running across some of the network, and none at all in others.
Output:
Results of a ballot on a deal aimed at ending a dispute between train drivers and rail operator Southern Railway are due to be announced later.