Re: home signal

[mauried@tpg.com.au (Maurie Daly)]

In article <3910F2C9.464C7488@fastlink.com.au> Railway Rasputin II <bob@fastlink.com.au> writes:
>From: Railway Rasputin II <bob@fastlink.com.au>
>Subject: Re: home signal
>Date: Thu, 04 May 2000 13:47:21 +1000

>Hmmm more fairy tails.


>> A 'Home' signal is the first signal reached by a driver on approaching
>> an interlocking area, and which actually affords the protection for the
>> junction, crossing, or other risk. 

>Ok how about a Home Signal protects and interlocking or risk area such
>as a level xing?


>The next 'stop' signal past the home
>> signal is known as the 'second home', the next is 'third home' etc etc
>> etc. 

>And what about a starting signal?? It can be at stop an areas that only
>need one home.

>If the need arises (such as if there was a ground frame just
>> before the Home), an 'Outer Home' signal is placed before the 'Home' to protect that. 

>Hmm How about an Outer Home protects the "netural zone" ie sidings,
>space for shunting movements to be carried out within the yard limits?


>FYI there are a couple of other types of signals such as
>> in single lines which are inherently bidirectional, a 'Distant' signal


>Distant signals are also used on double lines as well including the main
>south.

>> which is placed at braking distance in rear of the home and gives the
>> driver advanced warning of the state of the home. In little used lines
>> the 'distant' is replaced by a 'landmark' (a retro-reflective yellow
>> triangle). 

>The landmark signal is in place where all trains must proceed with
>caution to the home as opposed to a distant which has two postitions
>full clear and caution.
>There are 3 types of Landmark signal.
>Non reflective with a light, non reflective yellow with cats eyes
>reflectorand the retroreflective type that you have mentioned.


>In Automatic signalled areas (unidirectional lines) the last
>> signal approaching the 'home' is called the 'Accept' and it too is
>> placed at braking distance to the home. 

>The accept signal is the first controlled signal after an automatic
>section. 
>The signals reading from an
>> interlocking into a single line (bidirectional line) are
>> called 'Starting' signals and they give the driver authority to proceed
>> into the block (providing there are no other safeworking procedures to
>> adhere to such as train staff).

>Starting signals when cleared allow the train to proceed into the
>section provided they have the correct authority/token.
>> 
>> Anyway I hope this explains it. As to 'what operates a home signal',
>> well a lever or push button does. But I guess you're not really after
>> that type of answer :-)
>> 
>> cheers
>> 
>> Ian Hayes
>> Railway Signal Design Engineer

>Source: Safeworking Signalling Manuual and Basic Safe Working Manual.

>rgds

>rgds


There is from the other posts about this thread a huge variety of 
circumstances in which signals are defined as home signals ,and given the 
large range of differant signalling regimes in use in Australia ,I suspect 
that its not possible to accurately define what a home signal is.
It may be however,easier to define what a home signal isnt.
How about this.

A signal which can be passed at stop without any form of external authority is 
not a home signal,so therefore all signals which dont meet this criterion are 
home signals.
I reckon this gets most of them.

MD