Quote:
Originally Posted by John_142
As i use the Ormskirk to Preston Line fairley regular and was wondering what is the token actually used for ie What is its pupose.
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Well this is going off at a bit of a tangent to the discussion we were having about AWS/TPWS, but the pupose of a token is usually to give the authority to be on a section of single line. The token equipment is set up so that only one train can be in section at any time. The only way that signals can be cleared to allow the next train into section is by the previous train coming out of the section and its
token being returned to the token apparatus, to prove that the line is now clear again and enable the interlocked signals to be cleared.
Although it's a clever arrangement, mistakes can still be made. I always think of the Abermule disaster when I think of tokens.
http://www.bbc.co.uk/wales/mid/sites...ule_1921.shtml
Tokens can either be
physical lumps of metal which are passed to the driver at the beginning of the section and 'surrendered' once the train comes out of section, or they can be
virtual as in the the case of Radio Electronic Token Block (RETB) whereby a token is passed to and from the train electronically.
(I mentioned Single Line Working in one of my previous posts. This is a temporary arrangement whereby a Pilotman "on the ground" controls movement in both directions over a single line with the Signaller's authority, usually because engineering works are blocking one or more running lines. Here the Pilotman issues Single Line Working Tickets, which are a
temporary form of token. As a driver these have to be cancelled once you have come out of the Single Line Section. One 'comforting' aspect for drivers is that it's a rulebook requirement for the Pilotman to ride with you on your train if you are travelling towards an obstruction. When this happens and the Pilotman is sitting next to you on the footplate you know you're doing it right !
HTH
Foggy