Mr Ayson was asked to paint a mural on one of the trucks several years ago and he now has seven paintings displayed on trucks.
"I am very appreciative that Ray Terry has given me the opportunity to be able to display my art work on such a large mobile canvas," Mr Ayson said.
His latest paintings are related to the Otago Central Rail Trail.
They depict scenes from the days when steam trains were plying the line.
They include a scene from the Alexandra railway station and one of the steam train crossing the Poolburn viaduct.
Previous paintings have included a curling scene, Mt Cook, Lake Hayes, Alexandra in autumn and a dredge scene.
While the first truck paintings were done by hand, modern technology now makes the work easy.
Mr Ayson begins by painting a scene in acrylic on canvas about 1m x 0.3m.
That is photographed using a digital camera and then the digital information is fed into a signwriter's computer.
The printer produces the painting in sections and it is attached to the truck.
Mr Ayson has also painted a large mural on the side of the Terrace Distributors warehouse which gives people on the rail trail an immediate view of what it used to be like when trains called at the Alexandra railway station.
The site of the old railway station is directly across the road from the warehouse.
