A video shows the hilarious moment a woman gets onto a Sydney train and mistakes Prime Minister Malcolm Turnbull for a train conductor.

The video, filmed by David Sharaz, shows Mr Turnbull standing at the door welcoming passengers onto a train heading to Emu Plains in western Sydney on Wednesday morning.

As the woman climbs up into the train from the platform, Prime Minister Malcolm Turnbull says to her: 'Hello, do come on - how do you do?'

She looks at him and replies with: 'Good thank you. And who are you?'

Mr Turnbull looks momentarily bemused before replying with: 'I'm ahh doing a bit of conducting on the train.'

The woman then replies with: 'Oh that's good!'  

Mr Turnbull was on his way to Emu Plains for a community morning tea with business owners and mothers at Penrith Gallery with the member for Lindsay, Fiona Scott. 

The Prime Minister and opposition leader Bill Shorten are on Day Three of an eight-week campaign in the lead up to the July 16 federal election.

On Monday morning Mr Turnbull visited the Brisbane Produce Market in the seat of Morton, sampling some watermelon and reminiscing with bystanders on his younger days when he once stacked watermelons onto trucks.

Later that day he headed to Townsville. 

Mr Shorten kick-started his campaign talking about education at a Cairns school in the Liberal-Nationals seat of Leichhardt.   

On Wednesday while Mr Turnbull remained in western Sydney, opposition leader Bill Shorten touched down in Mackay to speak about schools funding.