Absolute & Automatic are two types of signalling system in a block section
The section controlled by the Station Master is called 'station section' . A station section territory usually begins with the First Stop Signal/FSS (which is Home Signal) and ends with Last Stop Signal/LSS (which maybe Starter Signal or Advanced Starter)
Rest...
more... of the section which is not governed by any Station Master is called block section.
• Absolute block system: Here we shall only speak about the 'block section'. In case of Abs block sys, to allow a train into this block section, the SM of the station (let A) , has to obtained 'line clear' from the station in advance (let B).
Here 'line clear' means the section between Starter/Adv Starter of Station A upto the Home Signal of Station B needs to be clear. Apart from this criteria, there maybe many more technical requirements for SL/DL section which I'm not getting into.
• Automatic block system: Here SM does not need to ask any other station, he usually has to pull off the signal from his pannel only.
Pull off means to give signal, from ON condition to OFF condition.
Red aspect is called ON condition & any other aspect is called OFF condition.
In Auto block, a signal simply displays the aspect, based on the aspect of the signal in advance of it. It certainly has axle counters & glued joints.
Double Distant: A distant signal, is available in Abs block sys. & is simply a predictor signal, of the signal standing in advance. Its working properties is similar to An Automatic signal, the only difference is, a distant signal doesn't have any axle counter or glued joint, so its aspect doesn't respond to the passing train, i.e, a distant signal will never turn to red if a train passes over it. Its aspect changes with the signal standing in advance of it. A home signal, gate signal usually has a distant signal or predictor signal.
Now, during launching of high speed trains, a necessity was felt for an extra distant signal along with existing distant signal. So the concept of Double distant came in... A double distant can be identified by observing the yellow-black stripes on the signal post (in the attached picture)
You will find several videos in YT explaining the working
please wait...Translate to EnglishAbsolute and Automatic are two types of signaling systems in a block section.
The section controlled by the Station Master is called the "station section." A station section usually starts with the First Stop Signal (which is the Home Signal) and ends with the Last Stop Signal (which can be the Starter Signal or Advanced Starter).
The rest of the section that is not controlled by any Station Master is called the block section.
• Absolute block system: In this system, we will only talk about the block section. In the case of the Absolute block system, to allow a train into this block section, the Station Master of Station A has to obtain "line clear" from the station in advance (Station B). "Line clear" means that the section between the Starter/Advanced Starter of Station A and the Home Signal of Station B needs to be clear. There may be other technical requirements for the SL/DL section that I'm not going into.
• Automatic block system: Here, the Station Master does not need to ask for any oth...
