There are many different types of tankers on the Island of Sodor used to carry various kinds of liquids. They usually have had very little influence in stories. They are also referred to as wagons or trucks and were only depicted with faces in the fourth season episode, Toad Stands By.
There are black, white, brown, silver, grey, and yellow tankers used to carry various liquids.
The fuel tankers are painted yellow with pictures of fire in red diamonds and "SODOR FUEL" in black on both sides. They are used to transport fuel. In the thirteenth season, the words "Sodor Fuel" were removed and a red gas can has taken their place.
Fuel has also been transported in black tankers, and yellow tankers without any labels.
The title "Sodor Fuel" is an in-joke. Apparently it was supposed to sound like "Sod off, you all."
The oil tankers are painted black with "OIL" in white on the side. There are also a number of older, dirtier oil tankers that can be seen around Sodor. The utmost care must be taken with these in case of fire, as Jamesonce found out when his tankers caught fire. He then was usually seen hauling them during the New Series.
The Milk Tankers are painted white with "TIDMOUTH MILK" in blue on the sides. They are used to carry milk from local farms to the dairy at Elsbridge. Toby collects one from the dairy each morning on his way to Anopha with the quarrymen, and leaves it at Ffarquhar to be loaded. After being loaded, the van is coupled behind Clarabel and taken to the dairy on Thomas' first train. While Thomas was away having his front mended, a Diesel railcar named Daisy was brought to do his work. Daisy, who was then a lazy sort, did mind, and refused to pull the van, and so much to their annoyance Toby and Percy had to make special trips to deliver the milk. However, now that Daisy has learnt sense, she sometimes takes the milk instead of Thomas.
From Misty Island Rescue onwards, the words "TIDMOUTH MILK" have been replaced by a logo of a cow in a blue circle.
Jam Tankers, known as Jelly Wagons in the US, are tankers which carry jam. They are painted silver and grey. In the ninth season episode, Respect for Gordon, Gordon collided into them and jam went flying everywhere.
Diesel tankers carry diesel fuel. They are painted black with a red triangle on the sides. They first appeared in the magazine story, Magpie Mavis. In the eighteenth season, diesel fuel is transported by oil tankers.