The new franchise will include services currently run by Southern
More railway stations in the South East are to be staffed at night and more will have ticket gates, the government has announced.
The move follows public consultation as part of the process to award a new South Central rail franchise.
Four companies have been shortlisted to bid for services in south London and parts of Surrey, Sussex and Hampshire.
The Department for Transport (DfT) said the initiative would increase security and reduce fare dodging.
Transport minister Andrew Adonis said: "We have worked closely with rail user groups such as Passenger Focus to develop these requirements.
"The South Central franchise provides a vital commuter link into London from the south coast and provides important linkages into south coast towns such as Hastings and Worthing.
"By setting more robust requirements for bidders, we are ensuring future rail passengers have frequent and reliable services that are comfortable and safe."
National Express, Stagecoach, Govia and NedRailways are contesting the new franchise and were formally invited to submit tenders on Monday.
The new contract will start on 20 September 2009.
The DfT said that new ticket gates will be installed at 14 stations in south London before September 2009.
Another 15 stations outside London will have new gates, and those at locations such as Worthing, Eastbourne, Chichester, Lewes and Horsham will be staffed for longer.
All trains will be fitted with CCTV and an extra 1,500 secure cycle bays would be provided at stations - 500 more than originally announced.
The government has already said there will be 1,000 extra car parking spaces.
The new franchise will have 10% more capacity than existing services.
Other changes already announced include later services from central London to Sutton, Tulse Hill and Crystal Palace and on the Uckfield line.
There will be a new Sunday service between Brighton and Southampton and pre-paid Oyster cards will be valid across much of the franchise area.