Nelson is a ballast tractor.
Scammell Pioneer ballast tractor
Nelson usually transports other vehicles from The Pack, which made him wonder how'd it be like to get carried himself. He got his wish after he helped Thomas to the Fitters, but was needed at a different location quickly, so Percy took him there instead.
Nelson is a clever, intelligent, and wise ballast tractor who often feels overworked but never complains. He is proud of his paint and is happiest when he looks his best. Although he will never offer up a complaint, he is the first machine to comment on what is going wrong on the construction site.
Nelson is black with cream lining, red alloy wheels and a front beam. He has his name painted on his front cab above his windows and has his number written on his cab doors in cream.
- Season 2 - Max, Monty and the Bull (cameo), Stanley and the Flood (does not speak), and A Happy Day for Alfie
- Season 3 - Jack and Alfie Swap
- Season 4 - The Missing Tool, Too Much of a Good Thing (cameo), Duck and the Coaches (cameo), and George Strikes Again
- Season 5 - Nigel, Bumble Bucket