Toby is old but wise, hardworking, and knowledgeable enough about running branch lines. He is also savvy enough to control the trucks. However, his advanced age and design means that he is weaker than the other engines. While Toby is always ready to work hard, he can be a bit temperamental sometimes, especially when young and inexperienced engines who are full of themselves make things difficult for him. However, he can also have moments when he's a bit nervous and work at the quarry line often soothes off his moods without any cause of grief to anyone, except of course his old faithful coach, Henrietta.
He can also be placid and easy-going, enjoying the peace and quiet of the countryside.
Toby is based on a GER Class C53 0-6-0T Wisbech steam tram (reclassified as J70 by the LNER) built at Stratford Works. The J70 started their career on the Great Eastern Railway. They spent most of their career on the Wisbech and Upwell tramway pulling slow goods trains and, until 1927, passenger trains, though several were also assigned to the docks at Ipswich and Yarmouth. The first withdrawal came in 1942. Eventually, the sole survivor of this class was withdrawn from service and scrapped at Stratford Locomotive Works by 1955. They were replaced by BR Class 04s, Mavis' class.
Toby has consistently been painted brown with grey sideplates and cowcatchers. He has the number "7" painted on his sides in yellow with a red border.