Douglas is a twin Scottish tender engine. Donald is his twin.
- Plarail and Motor Road and Rail version (copyright "TOMY", 1999-2000 - JP; 2006-2009 - UK)
- TrackMaster by HiT Toys Company version (copyright "HiT Toys Company" ; 2008-2009 - US")
- TrackMaster by Fisher-Price version (copyright "Mattel", updated face identical to Donald, updated drive unit, no sticker windows, updated number and nameplate, grey traction tires, plastic tender axles, two holes in every wheel; 2012-2014)
- Douglas with red Troublesome Truck (Motor Road and Rail, TrackMaster [TOMY], TrackMaster [HiT Toys Company])
- Douglas (TrackMaster [HiT Toys Company], TrackMaster [Fisher-Price])
- Snowplough Douglas (Plarail)
- The first individual Motor Road and Rail release of Douglas was released eight years after the initial release of Donald.