Signalling Relays

 
  awsgc24 Minister for Railways

Location: Sydney
The most common type of signalling relay in Australia would be the BRB Q-type plug-in relay of the 1950s, and used in NSW since about 1968 at Campbelltown and Broken Hill, and 1973 at Hexham-Metford resignalling.

These relays are still being used with Computer Based Interlockings, such as the ECRL, primarily for interface circuits, those these relays can be replaced by electronic switches.

Large obsolete proprietary plug in relays are still used at Gosford, and between Hamilton and Newcastle, but these are likely to be replaced in the near future.

Level crossings use a special relay that operates the flashing lights.


Old Shelf relays with hardwired terminals go back to the 1920's and before. There may be very few of these left. How big and heavy were these?


Railpagers are requested to add to this necessary incomplete information.

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  stopblock Junior Train Controller

Location: Planet Earth
This is a specialised subject and one that not a lot of Railpage subscribers would normally respond to, but I for one am interested. Do we have any other takers for this discussion/thread?
  Ballast_Plough Chief Commissioner

Location: Lilydale, Vic
Prior to the Harmon Level Crossing Predictors installed at Puffing Billy, I know the majority of level crossings had BT1B and BL1B track relays - not sure what model though.
  awsgc24 Minister for Railways

Location: Sydney
Prior to the Harmon Level Crossing Predictors installed at Puffing Billy, I know the majority of level crossings had BT1B and BL1B track relays - not sure what model though.
Ballast_Plough

BT1B  - Large size plugin Track relay DC say 2V
BL1B  - Large size plugin Line relay DC perhaps 12V??
  stopblock Junior Train Controller

Location: Planet Earth
Shelf Relays
Yep, big, bulky and quite heavy (for a relay).

And yes!! they need a strong shelf to be placed on.





[img]http://farm6.staticflickr.com/5331/9606546826_d66c8b1398.jpg[/img]
http://www.flickr.com/photos/cross-wire/9606546826/
  awsgc24 Minister for Railways

Location: Sydney
Shelf Relays
Yep, big, bulky and quite heavy (for a relay).

And yes!! they need a strong shelf to be placed on.





[img]http://farm6.staticflickr.com/5331/9606546826_d66c8b1398.jpg[/img]
http://www.flickr.com/photos/cross-wire/9606546826/
stopblock
These two relays are probably DC types, as noted by the two large coils on each.

They could be 50 or more years old, but every ten years or so they are sent to the workshops for maintenance.

The stickers "1996" and "1989" are the dates of the last visit to the workshops.

When this is done, all the wires have to be unscrewed, with the muts removed, so that the mass of cables can be lifted off in one piece. These wires are single core cables which are stiff and retain their shape so that they can be lowered again onto a replacement relay.

If a circuit has to be connected with a flexible wire, the one-core and flexible wire have to be connected via a wire-change-terminal.

Some shelf relays are contained within a cubic box about 30cm x 30cm x 30cm, with all the terminals on the top (up to 12 contacts). These can be wired through a "top-box" to simplify the process of exchanging relays.
  stopblock Junior Train Controller

Location: Planet Earth
So awsgc24!
What value do you think these 50 years old or so relays may realise, either as they are, or in operating condition?

What I am asking is, other than you and I (and ballast plough from south of the border) is there any sense in trying to preserve such things, and if preserved, is there anyone left who knows how to perform the required routine maintenance necessary to keep such museum items working, and in what environment is it possible?
(You seem to know that they are supposed to be workshopped every 10 years!!)

Telstra still sponsors the Overland Telegraph museum, historic exchange equipment in each state, morse code telegram operator conventions and other PMG/Telecom things related to its history. CEO David Thodey is an avid supporter of Telstras communications history. The clicking of relays may still be heard in the Telstra museums in each state, but is anyone REALLY interested in hearing the clicking of railway signaling relays???  

Your thoughts

regards
Stopblock
  awsgc24 Minister for Railways

Location: Sydney

What value do you think these 50 years old or so relays may realise, either as they are, or in operating condition?
stopblock
Why do we have a A-R-Historical-S?

Why do we have a R-T-Museum?

Why do we have a Signalling Museum thread; see: http://www.railpage.com.au/f-t11374827.htm

Why do we have a Electric Staff thread; almost obsolete in NSW, but what about other states?
See: http://www.railpage.com.au/f-t11370656.htm

Why indeed? "Wasting time and bandwidth since 1992", or so the RP intro says. Smile
  historian Deputy Commissioner

From a Westinghouse Catalogue, probably from the '50s.

A DC relay similar to the one illustrated would be around 18.5 lbs, with dimensions about 9"x8"x9". Smaller versions existed (with fewer contacts), and these could be down to about 9lb

An AC (vane) relay is much heavier. A typical example, the H2, was 29lb with dimensions about 10"x9"x10.5". With a detachable top, this went up to 38lb with dimensions 10"x9"x12".

The early large type plug-in relays (bigger than the BR design) were smaller, and lighter than a DC relay. A typical DC one weighed 11lb, and measured 3.25"x9.75"x8.5". An AC vane one weighed 16lb and measured 6.5"x9.75"x8.5".

One thing to note, the move to plug-in relays was a conscious trade-off between size and efficiency. One reason the shelf type relays were so large and heavy was that the magnetic circuit was designed to be efficient and use little power to hold up. By the fifties, power supplies had improved (particularly for the large relay schemes coming into use) and so a higher power consumption could be tolerated, but large relays couldn't be.

You can do the conversion into metric yourself, 1lb is 0.45kg or 9lb is roughly 4kg. No wonder I sweated a bit carrying an AC Vane relay with top home from Spotswood Smile

Of course even older relays are even larger and heavier. Try a polyphase relay!
  awsgc24 Minister for Railways

Location: Sydney
From a Westinghouse Catalogue, probably from the '50s.

A DC relay similar to the one illustrated would be around 18.5 lbs, with dimensions about 9"x8"x9". Smaller versions existed (with fewer contacts), and these could be down to about 9lb

An AC (vane) relay is much heavier. A typical example, the H2, was 29lb with dimensions about 10"x9"x10.5". With a detachable top, this went up to 38lb with dimensions 10"x9"x12".

The early large type plug-in relays (bigger than the BR design) were smaller, and lighter than a DC relay. A typical DC one weighed 11lb, and measured 3.25"x9.75"x8.5". An AC vane one weighed 16lb and measured 6.5"x9.75"x8.5".

One thing to note, the move to plug-in relays was a conscious trade-off between size and efficiency. One reason the shelf type relays were so large and heavy was that the magnetic circuit was designed to be efficient and use little power to hold up. By the fifties, power supplies had improved (particularly for the large relay schemes coming into use) and so a higher power consumption could be tolerated, but large relays couldn't be.

You can do the conversion into metric yourself, 1lb is 0.45kg or 9lb is roughly 4kg. No wonder I sweated a bit carrying an AC Vane relay with top home from Spotswood Smile

Of course even older relays are even larger and heavier. Try a polyphase relay!
historian

Thank you for some most interesting and useful facts.

AFAIK, the common "19-inch" rack used for all sorts of electronic equipment these days, were originally designed for Railway Signalling Relays, probably the shelf relays. Surprised

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