Page 481 - IRSEM_Main Book

Para No. 20.2.4 Annexure: 20-A1

Automatic Signalling Scheme with OFC, MSDAC & OC

Brief context

The automatic signaling is implemented usually with DC track circuit, AFTC, Universal
Axle Counter (UAC), Single Section Digital Axle Counter (SSDAC). Any Failure of auto signals
will have cascading effect on Trains.

In order to have much better availability, Optical Fibre Cables (OFC) along with Electronic
Interlocking/Object Controllers and Multi Section Digital Axle Counters (MSDACs), with dual
detection may also be used for Automatic Block Signalling (ABS)

I. Introduction

The scheme is explained for a typical block section consisting of three Automatic Block
sections. The scheme consists of two components. One is controlling of aspects of Automatic
signals based on the clearance of tracks ahead and other is Train/track detection for block
section.

(a) Signal aspects are controlled using Object Controllers, placed at controlling Auto section
Goomties.

(b) Continuous Train/track detection is achieved through MSDAC (Dual detection).

For Installing the above two equipment along with necessary power supply, Auto
section Goomties are provided in the block section, with each Goomty catering for one UP
& one DOWN Automatic Signal.

II. Description of the Scheme

A. Auto Goomties

UP and DOWN Auto signals are planned in such a manner that, they are near to a Auto
goomty to drive them. An Auto Goomty (AG) (Relay hut) , works as RBG room for
controlling these UP and DOWN Auto signals as shown below.

Fig 1. Auto Goomties for controlling One Up & One Dn signal

Chapter 20: Automatic Block Signalling Page 427 of 535