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GN pointy blocks

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GN pointy blocks

Unread postby Richard Pike » Mon Aug 29, 2016 8:46 am

I found some more circuit diagrams for this type of instrument recently..

http://signalbox.org/gallery/e/spalding1-i.jpg

In the best traditions they ask more questions than they answer.

First the up block at Hertford North to Langley..

https://www.flickr.com/photos/32297024@N08/29007397000/

The commutator is locked by the arm of the up distant, fairly conventional but no ecconomiser contact is shown. Also D track circuit wont show clear until 49 and 50 arms are on. D track sound a buzzer as i've seen before if it occupies with the block at line blocked or line clear and alters the indication to line for the non pegger at Langley.

Next is the down block to Cuffley. An ecconomiser is shown in the commutator lock. Again the buzzer is present, sounding when A track occupies with the commutator is at line blocked or line clear, but this time there appears to be a switch to turn it of. Why was this provided?

https://www.flickr.com/photos/32297024@N08/28674773793/

The box diagram for completeness..

https://www.flickr.com/photos/pwayowen/22212735023/
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Re: GN pointy blocks

Unread postby StevieG » Tue Aug 30, 2016 2:26 pm

FWIW Richard, some memories of visiting Hertford more than once (not sure if they all tie in with the technicals that you've described).

I thought I remembered, on both Blocks, having to 'press the little white button' to 'peg' to Line Clear, and to 'unpeg' from Train On Line ( not unknown to get a belt off the metal bevel plate surrounding the button, so tried to make contact only with the button itself).
Definitely remember 'the buzzer' if the said things weren't correct when the first TC dropped, and that D track required 50 and 49 put back before it would show clear [ not popular in fog or falling snow as, with no TC in the platform, you'd no idea if an Up train had even passed 50 (890 yards away) or 49 (450 yards), let alone thinking of when TOS could be given, until it either became visible or passed 48 (190-ish yards) onto F 'track'; - perhaps after calling at the station for however long (unless the guard had rung 'Tail lamp' in) : Don't recall whether the same applied with A 'track' and the Down Homes.]

Pretty sure both combined Blocks at Cuffley were also 'pointys' as you call them, including remembering an occasion when a buzzer went off because LC was still pegged when the first track went down, but I don't recall them having lock buttons, or the TCs staying lit until signals were back at 'ON'. I'll have to try finding my 48-ish year old and decrepit notes to seek clarification.

I think the only other 'pointy' I encountered (my first) was an only one of the six Blocks in 'Barnet South'**, which was for the Down Slow (Rear and Advance sections), but as there was only the single Home about 150 yards away and no berth TC, there were none of the complications of Hertford.

** - [ IIRC those for the Up Slow and Up Goods looked as if they might once have been 'pointys', but on my first seeing them in '68, appeared to have been converted to both having a pair of normal 'needle' indicators (that for the UG, being a Permissive line, had the 'yellow' "Line Occupied"-type faces instead of the normal 'Absolute' 'red' "Train On Line" or Train Entered Section" type).]

Hope all this is of at least some interest.
Last edited by StevieG on Tue Aug 30, 2016 8:45 pm, edited 5 times in total.
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Re: GN pointy blocks

Unread postby Richard Pike » Tue Aug 30, 2016 5:45 pm

I could see the arrangements with D track would cause some problems. The way things are set up it looks like tail lamp advice could be given so out of section could be sent and another train accepted.
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Re: GN pointy blocks

Unread postby John Hinson » Wed Aug 31, 2016 9:19 am

I don't know if you are aware, Richard, but the Down block you refer to is available for inspection if it would yield any useful information. From memory, the switch for the buzzer is not on the instrument. To me it makes perfect sense to provide a switch and it is the Up block that is more worthy of mention in not having one. The LNER/BR(ER) did not normally provide annunciators at all on berth track circuits but I am guessing they were provided for this type of instrument because you could have a situation where the indications differed at each end of the section. The switch has surely to be provided because the annunciator buzzer is otherwise sounding permanently (as it did on the Up) with the TC occupied. Given the significantly greater traffic south of Hertford it is possible the switch was a subsequent provision following complaints of distraction caused. With terminating traffic and subsequent shunting it would not necessarily be unusual to hold a train outside.

Digressing a little, this type of instrument has always intrigued me by its crudeness of operation - introduced in late GNR days but distinctly inferior to the existing Tyer's-type instruments. Quite how they got past the BoT's eye's amazes me - I have never seen any other instrument anywhere without a needle for the non-pegger. Those at Spalding appear to have been provided when the boxes were new in 1921 and those at Hertford probably in 1924, just into LNER days. I suspect they were the GN's first and only in-house type. It is widely documented that the GNR's signalling side was under financial pressure at this period with an unfair share of the funds being given to the locomotive side of things, so maybe they just couldn't afford to fill Mr Tyer's till.

The other thing that has always intrigued me with those at Hertford was that they were plated Cuffley and Langley although these were not the adjacent boxes. The intermediate boxes were "block huts" only opened according to needs, but nevertheless labelling instruments that way is rare. Now it seems the wiring diagrams were similarly marked . . . curious indeed.

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Re: GN pointy blocks

Unread postby StevieG » Wed Aug 31, 2016 11:32 am

John Hinson wrote: " .... the Down block you refer to is available for inspection if it would yield any useful information. .... "
(Always a little pleased whenever I see it, having known it in its original location!)
John Hinson wrote: " .... From memory, the switch for the buzzer is not on the instrument. .... "
I agree, unless it is, but is very unobtrusive.
John Hinson wrote: " .... To me it makes perfect sense to provide a switch and it is the Up block that is more worthy of mention in not having one. The LNER/BR(ER) did not normally provide annunciators at all on berth track circuits but I am guessing they were provided for this type of instrument because you could have a situation where the indications differed at each end of the section. The switch has surely to be provided because the annunciator buzzer is otherwise sounding permanently (as it did on the Up) with the TC occupied. .... "
Not so sure about this John, as in my experience, IIRC it always remained silent in normal, correct circumstances, including when the first TC became occupied with the Block already at TOL and the home signal(s) 'Off'; or I think, even if they were 'On'.
My impression had always been that the buzzer was only there to draw attention to the irregular situation of the TC showing occupied while the Block commutator and therefore the physically-connected mechanical 'pegger' 'pointer' indicator were not at TOL (or is it TES on these? - I forget), (and apparently, as Richard has found, the non-pegger indicator at the rear box [u]was[u] turned to TOL) : This was somewhat similar to the same general lines' area's (and others? - I knew at least one example on the WR) practice of having a bell alarm where a mechanical distant applied to a colour-light stop signal that was replaced to Danger by TCs beyond it; the bell sounding continuously if the Distant was still 'Off' when the C/L went to red.
So, like the means of silencing such a Distant's alarm bell was merely to replace the Distant back to 'On' [ just remembering now that the traffolite plate on the bell instruments usually read 'IF BELL RINGS CONTINUOUSLY REPLACE LEVER No. (X)' or similar], I feel fairly certain that the remedy to silence the Hertford, Cuffley etc. 'Block' buzzer was merely to move the relevant commutator to TOL, thus regularising the situation, and I would've thought, negating the need for a switch : But have I missed something - Do Richard's readings of the circuitry reveal a variation in circumstances which would also have triggered the buzzer, and which would have needed a switch after all?
John Hinson wrote: " .... With terminating traffic and subsequent shunting it would not necessarily be unusual to hold a train outside. .... "
I think that holding a train outside would not have caused the buzzer to sound, provided that the Block was at TOL (see my comments above).
Last edited by StevieG on Wed Aug 31, 2016 9:11 pm, edited 1 time in total.
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Re: GN pointy blocks

Unread postby Mike Hodgson » Wed Aug 31, 2016 2:05 pm

StevieG wrote:My impression had always been that the buzzer was only there to draw attention to the irregular situation of the TC showing occupied while the Block commutator and therefore the physically-connected mechanical 'pegger' 'pointer' indicator not being at TOL (or is it TES on these? - I forget), (and apparently, as Richard has found, the non-pegger indicator at the rear box [u]was[u] turned to TOL) :


Yes, it's Train Entered Section on these.
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Re: GN pointy blocks

Unread postby John Hinson » Wed Aug 31, 2016 3:26 pm

StevieG wrote:Not so sure about this John, as in my experience, IIRC it always remained silent in normal, correct circumstances, including when the first TC became occupied with the Block already at TOL and the home signal(s) 'Off'; or I think, even if they were 'On'.
[snip]

OK, that makes even better sense - sorry . . . wiring plans need immense concentration and time for me to follow and understand. So this was the GN's defence against the lack of an electric needle that would respond by itself. I wonder if all were so-fitted (assuming there was a track-circuit to do the necessary).

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Re: GN pointy blocks

Unread postby Richard Pike » Wed Aug 31, 2016 7:33 pm

A bit more of the diagram here..

https://www.flickr.com/photos/32297024@N08/29259390272/

Bayford is shown by two X's on the linewires. Track circuit A is cleared by 21 arm on. The starter at Cuffley is released by line clear but the way the relays is drawn suggest a DC neutral polar relay ecconomised by some unknown device just before the earth symbol.

The block lines to Langley have more X's, two show connections at Watton, with a third in the up block line elsewhere. I speculate this was at Stapleford Sand Siding? Did that box signal up trains only?

The modification to D track circuit was carried out in 1971. I have seen a GN pointy block with a Woolmer Green engraved badge. How prolific were they? With the required electric locking mechanism for the commutator they can't have been cheaper to make than a simple pegging block?
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Re: GN pointy blocks

Unread postby StevieG » Wed Aug 31, 2016 9:13 pm

Mike Hodgson wrote:
StevieG wrote:My impression had always been that the buzzer was only there to draw attention to the irregular situation of the TC showing occupied while the Block commutator and therefore the physically-connected mechanical 'pegger' 'pointer' indicator not being at TOL (or is it TES on these? - I forget), (and apparently, as Richard has found, the non-pegger indicator at the rear box [u]was[u] turned to TOL) :


Yes, it's Train Entered Section on these.
Thanks Mike; thought so : You beat me to it before I could dig out my slides of Hertford, Cuffley or Barnet South, to check.
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Re: GN pointy blocks

Unread postby Mike Hodgson » Wed Aug 31, 2016 10:39 pm

StevieG wrote:Thanks Mike; thought so : You beat me to it before I could dig out my slides of Hertford, Cuffley or Barnet South, to check.

You didn't need to check a photo - it's also so marked on those circuit drawings linked above.
But I do have the advantage of having seen that only a week or so ago when I collected the drawings on Richard's behalf :).
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Re: GN pointy blocks

Unread postby John Hinson » Thu Sep 1, 2016 3:33 am

Richard Pike wrote:The block lines to Langley have more X's, two show connections at Watton, with a third in the up block line elsewhere. I speculate this was at Stapleford Sand Siding? Did that box signal up trains only?

Yes, Stapleford was the other intermediate box but I don't think it worked one-direction only. You would need two block bells for that.

Richard Pike wrote:The modification to D track circuit was carried out in 1971. I have seen a GN pointy block with a Woolmer Green engraved badge. How prolific were they? With the required electric locking mechanism for the commutator they can't have been cheaper to make than a simple pegging block?

The GN may have been trying to reduce the cost of delicate needles, which I doubt they could make themselves so would have bought-in. I have no idea how many were made - Cuffley/Hertford and Spalding are the only places I know that used them extensively but as noted above and earlier, odds and ends were installed elsewhere. The GN lines had such a range of instruments (some installed by the LNER and BR) that it is hard to guess.

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Re: GN pointy blocks

Unread postby StevieG » Thu Sep 1, 2016 12:03 pm

John Hinson wrote:
Richard Pike wrote:The block lines to Langley have more X's, two show connections at Watton, with a third in the up block line elsewhere. I speculate this was at Stapleford Sand Siding? Did that box signal up trains only?

Yes, Stapleford was the other intermediate box but I don't think it worked one-direction only. You would need two block bells for that.
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Stapleford was as much of a full-blown Block Hut (BH) as Bayford and Watton, Richard, and is shown in the 1960 Appendix Table A as a Block Post in the same way (without special comment) as the others.
Stapleford was abolished earlier than the other two (c1964?), and AFAIK and seen photos suggest, firstly seems to have been the only one whose 5-lever frame never became 'covered-in', being awkwardly sited on the Up side close to the A602 underbridge, with the signalman's actual Block hut (well, the last one anyway) being opposite, on the Down side, and secondly that the sidings were on the Down side beside the station, with lever 3 of the 5-lever frame working the sidings - UM points (fixed diamond in the DM), the layout being apparently the same as at the other two but rotated 180 degrees.

As to 'Up line connected only' sidings, the only such location (north of Hertford, importantly; see below) which I heard of by repute (and which the Up side level ground at one time visible seemed to bear out) was at Waterford(don't know if it ever went by a different name), not too far north of HN's Up Distant. Anecdotes suggested that there were two GF connections with the Up road, but I have never seen record of the arrangements or layout, and have no idea how the GF(s) would have been protected / controlled, [ although a clue may be that the LNER box diagram of the full (presumably just-completed) Hertford North layout had a distant under No.47 Up Starter for the Sand siding connection south of there, which ought therefore to have had its own stop signal and perhaps a key-locked GF ].
Unfortunately I have found no reference to Waterford Siding/s (or a sand siding south of Hertford) in the 1942, 1947 (+ No.1 Supp.) or 1960 Appendices, the only item for this area of the line apparently being a long-standing Local Instruction (of a little interest telecoms.- wise) in all three, concerning locked emergency 'phones for guards use at several locations between Cuffley & Langley (but not Waterford).
Last edited by StevieG on Fri Sep 2, 2016 1:18 am, edited 1 time in total.
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Re: GN pointy blocks

Unread postby John Hinson » Thu Sep 1, 2016 4:10 pm

Waterford Sidings were still in place at 1968 according to photographs I have although severed from the main line and very lightly grassed. I suspect they were out of use by 1960 because the protecting signals are not marked on the 1960 1:10560 map. The 1923 1:2500 map, which would be just after doubling, shows only one connection into the Up Line (and one siding) although the protecting Home signal is half-way back along the initial single siding. There could have been another undrawn connection close to the signal, or perhaps added later when the second siding was added, or maybe it was the signal location that led to the "by repute" report of a second connection.
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Re: GN pointy blocks

Unread postby Pete2320 » Fri Sep 2, 2016 1:01 am

Richard Pike wrote:How prolific were they? With the required electric locking mechanism for the commutator they can't have been cheaper to make than a simple pegging block?

Were the electric locks provided from new? I doubt if block controls were universal when the instruments were new. Or perhaps the lock was seen as a simpler way of such controls.

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Re: GN pointy blocks

Unread postby Pete2320 » Fri Sep 2, 2016 1:10 am

StevieG wrote:I think the only other 'pointy' I encountered (my first) was an only one of the six Blocks in 'Barnet South'**, which was for the Down Slow (Rear and Advance sections), but as there was only the single Home about 150 yards away and no berth TC, there were none of the complications of Hertford.

** - [ IIRC those for the Up Slow and Up Goods looked as if they might once have been 'pointys', but on my first seeing them in '68, appeared to have been converted to both having a pair of normal 'needle' indicators (that for the UG, being a Permissive line, had the 'yellow' "Line Occupied"-type faces instead of the normal 'Absolute' 'red' "Train On Line" or Train Entered Section" type).]

Hope all this is of at least some interest.

Like these http://www.signalbox.org/gallery/e/maudfoster.php.

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