SOUTHERN Rail conductors are staging their second 24-hour strike today.

The walkout could see travel chaos for some of the busiest routes in the south as members of the RMT union started just after midnight.

The strike is part of a dispute over the role of guards as the union opposes a new on-board supervisor role and plans for drivers to operate the doors.

The rail company has said it is "evolving" the role of conductors so that staff on-board trains will no longer have to be responsible for closing doors, but they will have a more visible presence on trains.

The company has now warned that there will be no service on certain routes and a limited number of trains on others today.

Strikers have said they will be handing out leaflets to passengers warning them of the disruption.

RMT general secretary Mick Cash said: "Our members have been backed into a corner by this aggressive and unpopular company and have had no option whatsoever but to fight to defend the safety-critical role of the guard on these rammed-out and unreliable Southern routes.

It comes after union members held their first strike action on April 26 and they will be holding a protest outside the venue for the Department for Transport Rail Industry Day in London from 8.30am.

The RMT has claimed train companies nationally are "hell-bent" on removing train and station staff and accused them of putting profits before safety.

Customer advice issued by Southern ahead of the strike warned passengers that queuing systems would be in place at many stations, there may be long waits to board trains, and the company could not guarantee to get people to their destinations.

The company said Gatwick Express and Thameslink services would be largely unaffected.

But some services were expected to be extremely busy and some Gatwick Express trains would be unable to call at certain stations.

Limited services are expected to run until 6pm today and Southern Rail has said there will be no service running between Chichester to Havant/Portsmouth Harbour and Southampton Central but South West Trains and Great Western Railway services will operate as normal between Havant and Portsmouth Harbour/Southampton Central.

Passengers can find out more on the live updates here.