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Low Visibility Signal System Disclosure Number: IPCOM000199984D
Publication Date: 2010-Sep-23
Document File: 6 page(s) / 323K

Publishing Venue

The Prior Art Database


This disclosure describes a simple system that will replicate the distant signal post status right in front of the locomotive driver. This system equips the train driver with an accurate telescopic vision during low visibility situations like foggy nights and helps in avoiding signal jumping related accidents.

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Low Visibility Signal System

1. Introduction

This invention aims at providing the train drivers with an automated and accurate system to see the rail signal on the locomotive panel instead of straining their eyes to locate it on a distant signal post. The signal post is not clearly seen when visibility drops due to foggy conditions during winter nights which leads to accidents resulting in loss of life and


            . This system scans the current status of the signal display post and duplicates the scanned status on a panel inside the train engine.

2. Limitations of Current Systems

The current systems merely aim at alerting the driver of an approaching signal post or aim at increasing visibility of the area using special lamps. The existing fog signal systems deploy an explosive on the track near the signal post. When the train passes over the explosive, a loud burst is sounded to alert the driver of a signal post proximity. This is risky as it requires railway personnel to be present near tracks to replace the explosive after a train


 asses over it. There are high chances of railway personnel missing a replacement or getting seriously injured by an approaching train while doing so. Also this is an exhaustive mechanism, hence expensive. In all, this system is low on safety and accuracy and high on cost.

3. Description

This low visibility system consists of two components, FM transmitter and FM receiver. The FM

Transmitter is fitted at the signal post and is electrically coupled with the signal status generation and display circuit. This FM transmitter is capable of generating 8 distinct base frequency signals, F1, F2, F3, F4, F5, F6, F7, F8 which are modulated. Frequency values F1, F2, F3 correspond to the presence of three signal statuses RED, YELLOW, GREEN respectively. Frequency values F4, F5, F6 correspond to the absence of three signal statuses RED, YELLOW, GREEN respectively. Frequency values F7 and F8 correspond to the signal post meant for DOWN and UP trains respectively.

The transmission system draws power from the existing signal post power supply unit. 3 Input


          ,Y,G are available on the transmission system. These are electrically coupled to the lines feeding the signal post display LEDs. U/D or the Up/Down directional switch is set to the correct position during installation depending on the route for which it will be providing signal. Antennae F1-F8 radiate the highly directional signals corresponding to input frequencies. The antennae assembly can be rotated around an axis to be aligned properly in the direction of approach of the train. Once the antennae have been aligned (


         arallel or perpendicular to track depending on the antenna type) and the U/D switch pressed to indicate the direction of the route for which the transmitter is intended, antenna alignment system and direction indicator switch get permanently locked. This arrangement ensures tamper proof operation of an installed transmitter. Fig. 1 summarizes the si...