Deltic Preservation Society volunteers have successfully replaced a Napier power unit in 55009 Alycidon, one of three Class 55 Deltics the society owns.
The replacement power unit, weighing 13 tons, was lifted in at Barrow Hill, Staveley.
It last ran in 1981 and has had some £40,000 spent on it, with new hoses, fuel injectors, main generator and overhauled phasing case.