Isobella is a yellow steam lorry, who works for the Sodor Construction Company.
She once had to deliver a piano, but she lost control and ended up dangling over of the side of a retaining wall next to the railway line. Kelly then had to rescue her.
Later, she had to collect diesel fuel for the other machines when they all ran out.
Isobella is a hard worker, but does not like getting dirty. She can also be rather cheeky and temperamental.
Isobella is painted yellow with red lining. She has the number "22" painted on her sides in red.
Isobella is based on a Sentinel DG4 steam lorry with a flat-bed behind her cab. She shares the same basis as Elizabeth.
- Yuka Shioyama (Japan)
- In the Wooden Railway range, her name is misspelled "Isabella".
- In some promotional sketches of the Pack, Isobella is seen with a yellow four wheel trailer, which is not present in the show. However, this is present with her Wooden Railway model.
- Three of Isobella's faces were preserved by the Top Props preservation group.
- Isobella is the only female member of the Pack.