The service, which celebrates 50 years in November 2010 only lasted for a month before all the units were withdrawn literally overnight and a steam service reintroduced. This was because of transformer explosions which had occurred on test. However a further incident in which a guard was injured resulted in the units being taken out of traffic. The logistics of putting the steam service back in could not be achieved in today's railway. I think it was October 1961 when the Blue trains reappeared. The transformers were fitted with a cooling oil bath and a relay called the Buchholz Relay which would trip if any overheating occurred and render the unit dead until it cooled down. I had the "pleasure" of working with the Blue Trains and saw this to good effect one particularly hot summer's day when the service was severely disrupted because of overheating and dead units!!!
Added by Paul Strathdee on 19 November 2009.