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| Anim of engine with coloured steam | Large anim of engine | Small anim of engine | Uniflow design (pdf) |
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| Elpenor's engine | Elpenor's engine | First fitted in Rockabill | Currently in Elpenor |
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| Rockabill's original 2.5" x 3" | Forced draft fan | Stirling cycle engine drives fan | Narrow boat engine |