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Project: Signal Repeaters

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Project: Signal Repeaters

Unread postby abist » Fri Aug 19, 2016 2:49 am

Hello members,

This is my first post on this forum. My name is Anurag and I am a rail fan from India but currently living in US. I have been a rail fan since childhood, a time when steam locomotives were the ultimate rulers of Indian Railways (IR) on all the gauges. I had the fortune of living next to a busy trunk railway line far back in the past and there was a signal box or I should say a "B" class station (not sure what the BR equivalent is) manned by an officer, the Assistant Station Master (ASM) and a team of porters. This station had everything except the platform for passengers to board/de-board the trains. It had "Distant" signal, "Home" signal, "Starter" signal and "Advance" signal and of course "Directional" signals as well. This "B" class station had an array of 50+ levers for signals, points, point locks, gate lock lever and couple of spare levers as well. They also had an array of block instruments and plus instruments on a bench atop lever frame. One the instruments that had my attention was the signal repeater (or signal indicator in IR parlance, if I remember correctly). As members of the forum would know, the function of the signal repeater to repeat the aspect of the "out of sight" signal to the men controlling the movement of the trains. Soon after, IR introduced automatic route interlocking and upgraded the the signaling system too, which meant that semaphore were decommissioned, manual interlocking was removed and all the signals (those soul-less color light signals) and points were now operated electronically. For a rail fan, who was equally a semaphore aficionado, this transition was devastating but my so-called "contacts" in the railways had promised me to "gift" me a repeater, so I had hope that I would be getting a piece of relic. Unfortunately, that never materialized and it was soon forgotten and I moved on with life.

Recently, I read about signal repeaters being nothing more than galvanometers. It was just connected to the signal to which it was set to repeat and every time a lever was pulled to change the aspect of the semaphore, the current running to the repeater from a signal post would switch direction, causing the semaphore arm of the repeater to go in "On" or "Off" position. Now, you may ask why am I writing this? One of the main reasons was to join the community of semaphore signal aficionados and to get information on my project. From the (electro) mechanical point of view, I have the schematics ready, which I will share in due course. The piece of information missing from my briefcase are the dimensions of the signal repeater box. I know railways in Britain used both rectangular case and round case versions to house the signal repeaters and I am looking for a rectangular box housing for my signal repeater. Are there any dimensions that we need to consider like height, width and depth? Also, what would be the best alternative for the metallic signal post? I mean I have seen the kind of metallic contraptions that can be used as signal post but its technical name is escaping my mind.

I request the members of the board, especially those who have had the fortune of working or seeing these signals in their heydays to please provide me their suggestions, I will be grateful to them. This will be a childhood dream coming true and I have already waited for 27 years and cannot wait more. :)

Thank you everyone for reading this and thank you in advance for your comments and suggestions.
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Re: Project: Signal Repeaters

Unread postby John Webb » Fri Aug 19, 2016 9:22 am

Welcome to the Forum! Do take a look at http://forum.signalbox.org/viewtopic.php?f=8&t=6913 which describes work undertaken last year at St Albans South signal box (a preserved box in the care of a Preservation Trust) - the work includes the installation of a signal repeater and the switch on the signal arm to work it.

None of our signal repeaters are rectangular - they are all round, about 3"(75mm) in diameter and 2.5" (67mm) deep. Some have a square base about 3.5" (85mm) wide. As you will see from the photos in the above topic, there are two types of signal repeater, the majority have a replica 'arm', one looks more like a 'galvanometer'.

Hope this is of help.
John Webb
(Member, St Albans Signalbox Trust)
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Re: Project: Signal Repeaters

Unread postby JRB » Fri Aug 19, 2016 10:28 am

In recent years, most signal repeaters were round like John Webb's at St. Albans. Many earlier ones were in rectangular wooden cases and some have survived to recent times. British signal engineering firms, notably Westinghouse and its constituents, had factories in India, so Indian instruments largely followed British designs.
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Re: Project: Signal Repeaters

Unread postby abist » Fri Aug 19, 2016 11:28 am

John Webb wrote:Welcome to the Forum! Do take a look at http://forum.signalbox.org/viewtopic.php?f=8&t=6913 which describes work undertaken last year at St Albans South signal box (a preserved box in the care of a Preservation Trust) - the work includes the installation of a signal repeater and the switch on the signal arm to work it.

None of our signal repeaters are rectangular - they are all round, about 3"(75mm) in diameter and 2.5" (67mm) deep. Some have a square base about 3.5" (85mm) wide. As you will see from the photos in the above topic, there are two types of signal repeater, the majority have a replica 'arm', one looks more like a 'galvanometer'.

Hope this is of help.
John, thank you very much for the input. I am glad to know that you are involved in the restoration preservation work for these wonderful semaphores and every other instrument that was required for semaphore operation, including the repeaters. Kudos to your and your friends effort in this restoration project. The pictures are really beautiful. I found the information about signal repeaters being modified galvanometers from a blog post, whose author seems to be a train enthusiast from Britain.

http://janfordsworld.blogspot.com/2013/ ... art-5.html

You are right that signal repeaters in Britain used round housing or sometimes had round top with square base. In India, these were mostly rectangular as seen in the photograph in the link given below. The signal repeaters are kept on the either side of the bench above the lever frame.

http://www.irfca.org/gallery/Events/con ... ewsIndex=1

My repeater prototype will be up next week. I will keep the members posted.
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Re: Project: Signal Repeaters

Unread postby abist » Fri Aug 19, 2016 11:39 am

JRB wrote:In recent years, most signal repeaters were round like John Webb's at St. Albans. Many earlier ones were in rectangular wooden cases and some have survived to recent times. British signal engineering firms, notably Westinghouse and its constituents, had factories in India, so Indian instruments largely followed British designs.
Hello JRB, thank your very much for your input. You are right about Indian repeaters being the same design as old British ones, as it can be seen in the photograph on the link posted above in my reply to John. It is quite frustrating to see IR not being as much aware or caring about its heritage as it should be. After the ruthless termination of the steam locomotives from IR geography some 21 years ago, when the last time tabled steam run passenger was stopped, now the IR is on a spree to replace the semaphore signaling with multi-aspect color light signals, which are as exciting to watch as traffic signals on road intersections! While not being totally critical of IR, who have actually done "some" good job about restoring museum exhibits and plinthed locomotives to working condition and have a dedicated steam locomotive shed but I feel this isn't enough as IR should invite more volunteer participation from public. Hopefully, one day things will change for better.
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