Melbourne's trains could stop for up to 48 hours after thousands of train drivers, station workers and signal operators have overwhelmingly voted to take industrial action in a fight for better pay.

Within the next 30 days, 3000 workers running Melbourne's city rail network could stop checking myki tickets, refuse to wear their uniforms, or walk off the job.

Ninety-nine per cent of rail workers with the Rail, Tram and Bus Union (RTBU) voted in favour of industrial action on Monday afternoon.

The ballot follows a breakdown in negotiations between Metro Trains and the RTBU over a four-year wage deal, with talks now entering their fifth month.