Boco is a wise and friendly diesel engine.
- 1992-1993 (flat magnets, grey top, no roof line undated wheels)
- 1994 (flat/round magnets, white top, roof line, wheels dated)
- 1996 (smaller magnets)
- 2003 (Name on chassis)
- He is labelled as Boco instead of BoCo.
- The first prototype 1994 Boco used Daisy's body.
- Boco is a repaint from the Knapford Express Coach.
- The official description for 2003 Boco stated he was "back by popular demand".
- The 2003 Boco Character Card depicts the 1994 version.
- The 2003 Boco was not listed in the Yearbook, but was listed in the pamphlet.
- Although Boco was reintroduced in 2003, some of his earlier reintroduction version had 2002 on their wheels.