Re: [General] Information about block working

[Eddie Oliver <eoliver@efs.mq.edu.au>]

Ronald BESDANSKY wrote:
> 
> When a double-line manual track block  section ends at a 1) a terminal
> station; or 2) a station where the line becomes single (worked by OTS, ETS
> etc), how are trains accepted from the box in the rear? It would seem that
> all trains would have to be accepted under the "line clear but station or
> junction blocked" regulation. I think that is not normally allowed for
> passenger trains??

Despite the number of postings answering this question, a couple of key
issues have been omitted.

Firstly (although someone else DID say this), the term "manual track
block" is very confusing (and certainly not a valid term in any
Australian railway). Presumably just "manual block" was meant, but some
answers referred to other systems of the "track block" variety.

Secondly, there seems to have been an assumption in at least some
postings that the clearing point for manual block working was always
based on some distance beyond a home signal. Whilst this was commonly
true in Britain and sometimes true in Victoria, it was not normal
practice in NSW, where the clearing point was a designated LOCATION, not
a designated DISTANCE. 

For instance the commonest NSW situation was for the clearing point to
be the starting signal. However if there were two or more home signals,
the clearing point would often be the second of these, and so on. Of
course this clearing point was an appropriate distance beyond the home
signal.

All this means that the alleged difficulty about terminal stations was
non-existent. There would typically be an outer home before the first
home signal actually protecting points or other conflicts; the clearing
point would be some location inside the outer home signal (perhaps the
first "real" home signal, although not necessarily so).

Also someone brought accept signals into the discussion. Accept signals
(an exclusively NSW concept, at least in that terminology) exist in
automatic or track block areas, not manual block areas. In manual block,
"acceptance" is done by line clear being given on the block instruments.

Eddie