Re: Blockworking?

[G.Lambert@unsw.edu.au (Geoff Lambert)]

craigd@lios.apana.org.au (C. Dewick) wrote:

>In <851ga0$kv3$1@the-fly.zip.com.au> "Bradley Torr" <btorr@bigpond.nospam.com> writes:

>>I was wondering what exactly blockworking was? From what I've read on here,
>>it appears to be a rather primitive way of organising train movements, but
>>what does it involve?

>Ok, Block Working is where only one train is permitted in a section of track
>between two *locally controlled* locations at any one time. 

Not sure what the original context of the question was, but should a
distinction be made between "blockworking" and "Block Working"?  That
is, the former might mean a very generic railway concept, the latter
something specific, e.g. to NSW.  

If we mean something generic, then surely "blockworking" essentially
means the imposition of space-interval working under almost any
safe-working regime?

In any case, there seems to be three ideas of how the term "block"
arose:
* The line is divided into spatial  "blocks"
* A section of line is "blocked" when a train enters it.
* Early telegraph instruments (esp. GWR) had their needles held over
in safe positions by "blocks" of wood.
Evidence and argument for and against each can be found in the
signalling literature.  Sections of track are still called "blocks"
and instruments still carry the indication "line blocked".

GL