The last remaining working example of a mercury arc rectifier will be on display to railway enthusiasts tomorrow, Friday (26 July).
 
The Manx Electric Railway and Snaefell Mountain Railway get their electricity supply from 6 special substations, which convert the electricity to 550v DC that the tramcars need to operate.  Originally this electricity was provided by the rail company’s own power stations that were modernised in the 1930s for the supply to come from the grid provided by what is now the Manx Electricity Authority.  Each substation was fitted with a mercury arc rectifier (MAR) to convert the electricity to 550v DC.  This equipment is now life expired and, following the failure of the MAR at Groudle last winter, Laxey is the last working example on the Island although power is now supplied to the electric railway via a replacement substation provided at Laxey last winter. 
 
The mercury arc rectifier at Laxey’s former MER substation will be demonstrated during this week’s Manx Heritage Transport Festival. The doors of the substation, on Rencell Hill behind the Queens Public House, will be open on Friday 26 July from 11am to 3pm. 
 
Community, Culture and Leisure Minister Graham Cregeen MHK said: ‘The mercury arc rectifier is an impressive piece of early 20th century engineering and the demonstrations on Friday will be interesting for local people as well as enthusiasts.’
 
Meanwhile, discussions are continuing between the Minister, Garff Member of the House of Keys, Steve Rodan SHK, and local enthusiasts over the best way to preserve the MAR for the future.
 
Minister Cregeen added: ‘My Department recognises that the mercury arc rectifier was a very common form of producing DC electricity for transport networks and is historically significant as the first form of reliable equipment in this field.’