Re: Catchpoints - what are they?

[signal_spotter@my-deja.com]

Duh!! here we go again. If you cut and paste the diagram into Notepad
and then place the curser after (OL1 via P10N) and hit return, then put
the curser after OL1/4 and hit return, you should get a fair
representation of the diagram. Meanwhile I'm going back to school to
brush up on ascii drawings :-)

regards Ian

In article <8hf0fl$33c$1@nnrp1.deja.com>,
  signal_spotter@my-deja.com wrote:
> Joseph,
>
> It seems my previous attempt at drawing ascii representation of
railway
> lines didn't quite work. Hopefully this attempt will.
>
> Loop lines are the adjacent line to the main line. I'll try to explain
> it with a diagram.
>
>   -0-0 S1  loop line         S2 -0-0  / catchpoint P10A (OL1 via P10N)
> --+--------------0---------------+---/
>         T1       OL6      T2          \
>                  via P10R              \
>                                         \
>   -0-0 S4  main line    T4   S3 -0-0     \ points P10B  T6  OL1/4
> --+--------------0---------------+--------------+-----------0--
>         T3       OL6 via P10N        T5   S5 0-0-      S6 0-0-
>
> So hopefully the diagram worked out. Anyway the legend is as follows:
>
> -0-0   = signal, S1 denotes lever 1 etc
> --+--  = track with blockjoint
> --0--  = track with blockjoint that's an overlap point ie OL6 is the
> overlap extremity for S6 and OL1/4 is the overlap point for S4 and for
> S1 if P10 are reverse. OL1 is the overlap point for S1 if P10 are
> normal.
> T1     = track circuit name. A track circuit is an electrical circuit
> that detects the presence of a train. The blockjoints are the
> extremities of each track circuit.
> P10A   = the catchpoints operated by lever 10 (A end ie closest end to
> Sydney)
> P10B   = points also operated by lever 10 (B end ie furthest from
> Sydney)
>
> So the operation is as follows. With P10 Normal ie catchpoints open,
> points normal, you can signal a train from S1 (loop line) and S4
> (mainline) simultaneously as both signals have valid overlaps. S1
> detects T1, T2, T5 and (T6 when P10 reverse). So with P10 normal it
> doesn't look at T6. S4 detects T3, T4, T5, T6 and P10 normal.
>
> S6 detects T6, T5, (T4 when P10 normal), (T2 when P10 reverse).
>
> P10 points are called 'facing' for moves from S1, S2, S5 and S6
> and 'trailing' for moves from S3 and S4.
>
> Anyway I hope this helps explain it a bit better.
>
> regards Ian
> Signal Design Engineer
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
>


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