A NEW train service due to launch this month with longer carriages could be derailed by a dispute with unions.

The 12 carriage Gatwick Express service got off to a bad start on Saturday when a driver refused to take 30 passengers on the first running of the service – instead driving the empty train to the airport station and back to London Victoria.

Now train operators' plans to run a twice daily service for up to 1,300 commuters from Monday are under threat from possible industrial action.

Govia Thameslink Railway (GTR) has called on rail unions to put passengers first and allow the extra-sized trains to run.

But trade unions oppose further driver only services because of safety concerns.

The new 12 carriage trains are two carriages longer than those currently operating on the Gatwick Express route and GTR hope that they will make up half of all trains on the service by June.

GTR said more than 60 per cent of their services already run without a conductor or guard and the exact same trains already run without a conductor as Thameslink trains.

The rail operator said that the new 12 carriage trains, which will also run to Brighton station during peak hours, are only 14 metres longer than the ten car trains they will replace.

Rail unions are unhappy that they were given just one day of notice of the new service after receiving a second class letter on Friday.

They claim that the late notice was part of intimidatory tactics by rail operators.

The Associated Society of Locomotive Engineers and Firemen (Aslef) said it was opposed to extending driver-only trains beyond existing agreements it had with rail operators.

The union claims that all passenger surveys indicate support for conductors on trains and that it was a matter of public safety to have another member on board should a train driver fall ill at the controls.

A Gatwick Express spokesman said: “Everyone knows longer trains are a key part of the solution to improving the rail service for passengers.

“We urge ASLEF to put passengers first and drive these trains when they come into regular service next week.”

An Aslef spokesman said: “As a result of this threat to impose 12 car drive only operation passenger working without agreement GTR has been informed of our intention to ballot our driver members employed on Southern and Gatwick Express for industrial action.

“The formal balloting process will begin as soon as possible.”