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Nairn

British signalling of the past (UK, excepting Northern Ireland)

Unread postby JRB » Fri Mar 21, 2008 4:35 pm

Roger Bell wrote:I think the radio working of token instruments was instigated as the result of severe gales bringing down lots of poles on the Far North line. GPO phones were used immediately after the gales with OTW tokens or staff and ticket - does anyone have more info on this period before RETB?
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As I recollect, the tokens were interfaced with the radio by reed FDM as developed by the NYM Rly. rather than computers. I wasn't there however so could be wrong. The NYM did it to use tokens via GPO lines which could not be relied on to maintstain polarity. They never used the method in anger apparently.
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Unread postby Keith » Sat Mar 29, 2008 12:44 pm

JRB wrote:As I recollect, the tokens were interfaced with the radio by reed FDM as developed by the NYM Rly. rather than computers. I wasn't there however so could be wrong. The NYM did it to use tokens via GPO lines which could not be relied on to maintstain polarity. They never used the method in anger apparently.

Sorry John, the (former) BR Research people definitely used computers and, as previously mentioned, claimed the token instruments as the oldest computer peripherals in the world.
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Unread postby MRFS » Sat Mar 29, 2008 2:00 pm

Roger Bell wrote:I think the radio working of token instruments was instigated as the result of severe gales bringing down lots of poles on the Far North line. GPO phones were used immediately after the gales with OTW tokens or staff and ticket - does anyone have more info on this period before RETB?
Roger


It was written up in the IRSE proceedings for 1981-2 (I think); I'll have a scour around the ranch for my copy.

EDIT: Can't find it - but I've found a whole lot of other signalling gems that haven't seen the light of day in a long time.
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Unread postby MRFS » Sun Mar 30, 2008 3:53 pm

Found it!:

In Jan 1978 a blizzard destroyed 65km of overhead wires over a 160km section of the Inverness - Wick line [...]

Benefits of radio cost saving; yada yada

Staff and Ticket working using GPO telephones was instituted to maintain the service [...]

Other systems via radio; yada yada

It proved possible to restore token working, with its improved flexibility, by encoding the d.c. signals, normally carried on the line wires, as data messages on the radio system, using microprocessors for the data coding [...]

Commissioned Sept '79 for speech; signalling Aug '80
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Unread postby Keith » Mon Mar 31, 2008 5:48 pm

Thanks for that confirmation, MRFS. As I'm currently several thousand miles from my copy of the proceedings, can you say who wrote the paper? Was it someone from BR Research? If so, did he make the claim about the "oldest computer peripherals in the world"? Of course, it may have been added as an informal remark during the actual presentation, but more likely it was mentioned during one of my visits to the Railway Technical Centre while I was based down the road at the Railway Engineering School around that time.
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Unread postby Benhar Jnc » Mon May 19, 2008 10:07 pm

From a signalling design point of view, the arrangements at Nairn seemed rather unusual - prior to the boxes being closed. In Oct 98 a very pleasant signaller showed me how the system worked - including the bicycle ride!

The station itself, features a very lengthy platform - with an 'East' box and 'West' box at each end. I was left wondering, why the facing points giving access to the sidings were controlled by an additional ground frame.

For a location, that is in effect nothing more than a single track with a passing loop and a couple of sidings - the provision of two signal boxes, a ground frame and mechanical and electrical S&T equipment in the main station building - all seems a tad extravagant, but most interesting to observe.

Was this just a unique 'Highland' approach to controlling points and signals, or is there another reason?
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Unread postby SDL » Mon May 19, 2008 10:28 pm

The original arrangements at Nairn were absolutely typical of the Highland Railway. The loops were too long to be worked from one signal box, given the former 180 yard limit on the distance that facing points could be located from their levers.

The provision of a ground frame to control the connection to the sidings was done in preparation for an RETB scheme that never happened.
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Unread postby Benhar Jnc » Mon May 19, 2008 11:19 pm

Many thanks for the explanation - In particular I'd been wondering about the GF and why the West Box didn't simply control the points into the sidings. Had no idea that a the GF was preparatory work for a RETB scheme.
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Re: Nairn

Unread postby NAIRNMAN » Sun Jan 6, 2013 1:01 am

Key token block to Forres,track circuit to Inverness.I should know I worked it...bike and all,lol
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Re: Nairn

Unread postby Benhar Jnc » Sun Jan 6, 2013 5:32 pm

NAIRNMAN wrote:Key token block to Forres,track circuit to Inverness.I should know I worked it...bike and all,lol


Good to hear from Nairnman (obviously not 'Nairnwoman of 1998') who rode the infamous bike along that very long platform between the two boxes. When you were the signalman - Was entry to the yard controlled by a ground frame or did the frame in the West Box control it? I'm interested in how freight trains entered and left the yard and did you also round them? I remember the sawmill used to have some traffic in the days of yore.
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Re: Nairn

Unread postby NAIRNMAN » Thu Aug 21, 2014 12:01 am

It was controlled separately with an annetts key and just to confuse things the signalmen were never trained or shown how to operate this ground frame,the guards of the respective trains operated it.Almost always the timber freight train.
We as signalmen knew its workings but always the guard who opened the frame used the key and set the road into the yard.
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Re:

Unread postby Pete2320 » Fri Aug 22, 2014 3:26 pm

Roger Bell wrote:
Keith wrote:I don't think Nairn ever went through the stage of having "Radio Token Block" (note this is not RETB - it was used on the far north line while RETB was being developed), which was claimed to have the oldest computer peripherals in the world - as computers provided the interface between the token instruments and the radio.


I think the radio working of token instruments was instigated as the result of severe gales bringing down lots of poles on the Far North line. GPO phones were used immediately after the gales with OTW tokens or staff and ticket - does anyone have more info on this period before RETB?
Roger

That is my understanding but that normal working, ie ETB was restored by linking the token/tablet machines by radio. In the great scheme of things, this was actually a rather short lived era before RETB was introduced. As Roger has said this was ETB and in no way to be confused with RETB. Although there might well have been some local instructions concernig the equipment, the normal ETB regulations would still hold good. Roger also uses the phrase "while RETB was being developed". This was doubtlessley true but it gives the impression that the "ETB by Radio" was perhaps a form of stagework for RETB. That is not so although it may have led to the idea! I'm being a bit pernichity here as it is clear that the two systems are becoming confused and I can see that as time progresses that will get worse.
Incidentally, operation of various types of electric token machine by radio was (is) not unique to Scotland. It is used in Northern Ireland and South America- Argentina I think.

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Re: Nairn

Unread postby Wilkinstown » Sat Aug 23, 2014 8:10 am

"ETB by radio" was instituted in Northern Ireland over the 28 mile section between Castlerock and Londonderry following storm damage to the pole route. The solution as far as I am aware uses the same technology as that used on the Far North line and was installed around the same time. As far as I am aware this arrangement still applies although the line is scheduled for re-signalling in 2015 at which time the section will be split with an intermediate loop re-instated at Bellarena to support an increase in frequency from two hourly to hourly. Electronic key token working will be replaced by TCB and the existing signalling (controlled by a panel at Londonderry and a mechanical frame and semaphore signals at Castlerock) will de-commissioned. The loop at Castlerock is to be eliminated and Tablet working will also cease between Castlerock and Coleraine as part of the same re-signalling scheme.

I do remember the charming setup at Nairn and particularly the bicycle. I am aware of one location in Ireland where one the signalmen uses a bicycle to travel between the signalbox and the station level crossing (until recently interlocked by a separate ground frame, itself locked/released from the cabin). The bicycle remains in use as the signalman still also works the level crossing although the method of interlocking has been modified.
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Re: Nairn

Unread postby StevieG » Sat Aug 23, 2014 9:13 am

I seem to remember that the Nairn bicycle became recognised as officially necessary signalman's equipment, and was even pictured somewhere (Railnews perhaps?) in full Railtrack livery (green with gold/copper-coloured lettering?).
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Re: Nairn

Unread postby Mike Hodgson » Sat Aug 23, 2014 9:20 am

So would bicycle clips be considered to be part of the signalman's uniform, or were they part of the box's essential safety equipment since it would be dangerous for a signalman to get caught up in his bike chain, especially while riding along a high platform?
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