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Point rodding and signal wires


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Hi

I am getting ready to design how the point rodding and signal wires (non-operational) should run on my layout. I am modelling GWR c1929.

 

I think I have some idea of the basic principals involved i.e. to have the runs as direct and straight as possible. Before I progress too far it would good to know if anything was not allowed or very rare.

 

I have some questions in this regard as follows:

 

a) Was there a generally accepted maximum number of point rodding runs that could pass between two adjacent sleepers other than the physical constraints of the sleeper spacing. I am thinking here off the rodding as it emerges from signal box

 

b) Similarly with signal wires. Could a group of say 5 signal wires emerging from the signal box pass under track between two sleepers.

 

c) I can see that changes of direction were usually approximately at right angles. Would there have been a minimum angle for a change of direction using cranks. Would e.g. 80-85 degrees. have been acceptable?

 

d) Was it permissible to take runs across track underneath point work (when it wouldn’t have interfered with stretcher bars, Facing Point Locks etc.)?

 

e) Was there a limit to the number of times that a particular run of rodding or wires could change direction via cranks.

 

Regards

Graham

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  • RMweb Gold

I’ll try and help with some of these:

 

a) Was there a generally accepted maximum number of point rodding runs that could pass between two adjacent sleepers other than the physical constraints of the sleeper spacing. I am thinking here off the rodding as it emerges from signal box

Max 2 (or possibly 1 - too long ago and memory fade).  Generally, rodding runs left the box alongside the track, hence complications of the leading off bed and needing different height cranks to get it all sorted out.

 

b) Similarly with signal wires. Could a group of say 5 signal wires emerging from the signal box pass under track between two sleepers.

Not sure of any particular limit, though I can’t say I’ve seen that many, but also, I’ve not been on site with big gantries needing lots of wires.

 

c) I can see that changes of direction were usually approximately at right angles. Would there have been a minimum angle for a change of direction using cranks. Would e.g. 80-85 degrees. have been acceptable?

Don’t know, sorry.

 

d) Was it permissible to take runs across track underneath point work (when it wouldn’t have interfered with stretcher bars, Facing Point Locks etc.)?

I think so, but probably best kept clear of the crossing area (frog).

 

e) Was there a limit to the number of times that a particular run of rodding or wires could change direction via cranks?

Don’t think anything was specified, but the more cranks there are, the more difficult it becomes to operate the points as the cranks become worn and loose.  So, if I was laying out a rodding run I would try and minimise the number.  Having said that, I’ve seen photos of large runs that move under a trackbed to gain a different wide way which obviously adds 2 cranks to each rod.

 

Paul.

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Just a few photos for a start. BUT NOTE - this is on a heritage railway and although all of thos was installed under the direction of a WR S&T dept employee there are some significant differences in the way various materials are used.  However what you can see o is how a rodding run can run round a curve in the track.  In this case the vast majority of the leading off bed is on the opposite side of the line from the signal box but you can see in one image - if you enlarge it - the use of different height leading off cranks - looka th different depth of teh setts in the pinjoints connecting the crank to the channel rodding (it would be round rodding for your period).

 

to adda bit more in respect of various of your questions -

a).  - generally two but three at a squeeze)

b) - ideally no more than a couple because if wire run pulleys are used (fixed to the sleepers) there wouldn't really be room for any bigger than that however undoubtedly in some places  far more had to be squeezed in although the lever spacing would in fact dictate the number more than anything else.

c). - you can certainly get down a bit below 90 degrees with ordinary cranks - plenty of photos around to prove that and i laid out a run on a preservation site which was probably nearer 80 degrees than 90 which works perfectly well.  There was also a special single-ended crank used for some angles but they were not at all common.

d). - no but direction was never changed needlessly.  the important thing in planning and laying outa rodding run was to eqy uakise the amount of push and pull in the run as nearly as possible in order to allow for expansion and contraction and where necessary compensating cranks would be used to reverse the throw in a continuous run.

 

Run on a curve with a pair of compensating cranks opposite each other/. Look at the number of signal wires

 

1608885894_IMGP6978copy.jpg.3094aae8690538396cb788986f2642fb.jpg

 

623107699_IMGP6978copy.jpg.7f0bd7c35495c9b9c7bd7139e86e5107.jpg

 

 

Rodding under track - note the special ri oller used in the four foot

 

717832583_IMGP6983cr5copy.jpg.6aad16afce3b0bf131056f2d9e8eabe7.jpg

 

1643609849_IMGP6983cr5copy.jpg.6d426e35878e366b34704357ea50b288.jpg

 

Curved rodding run in the opposite direction to the first photo and the 'sprt of' leading off bed opposite the signal box where you can see some stepped leading-off cranks

 

291300896_IMGP6980copy.jpg.c610b5a860fed6853665d1bd4f8fa6f1.jpg

 

 

1656753237_IMGP6980copy.jpg.32bd59bc20a78d77fb71532e579f83c3.jpg

 

Edited by The Stationmaster
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Perhaps worth noting that rodding outlet from the box is often at the front with cranks to turn it parallel to track, and as seen in the photos above, the number of rods cranks etc required means box structure isn't right bang up at minimum clearance from the running rail.  - And this area might well be boarded over where there is a need to walk over it.

 

Rodding can also emerge from ends or back of box.  All of these openings tend to be the source of horrendous draughts in the box, which is why old carpets may be thrown over the quadrants where there is a run of spare levers/spaces.  The wooden infill pieces with holes for the rodding as seen the last of Mike's views is another way of minimising draught.   

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  • 2 weeks later...

Hi

I have trying to display my ideas for point rodding and signal wire runs in a way that was not too confusing. My theoretical lever frame layout is as below. First of all, would this be realistic? I have basically worked off the system at Bodmin modified for my design. It seems to me that this would allow the shortest and simplest way of laying out the runs. I have spent many hours trying to come up with a diagram that is understandable, as attached. Most of the runs pass to outside mainline or between mainline and loop.

 

1. Signal Advanced Starter Mainline

2. Signal Advanced Starter Branch 1

3 Signal Platform Starter

4 Signal Starter Mainline

5 Signal Starter Branch 2

6 Spare

7 Spare

8 Point Slip

9 Signal Ground signal for Branch 2

10 Signal Ground signal Loop to Mainline

11 Signal Ground signal for crossover

12 FPL for 13

13 Point Mainline to loop

14 FPL for 15

15 Point to Branch 1

16 Point Mainline to Branch 2

17 FPL for 16

18 Signal Ground Signal Engine Shed

19 Point Engine shed/carriage siding and catch point engine shed

20 Signal Ground Signal Carriage siding

21 Point Mainline to sidings carriage and engine shed and catch point carriage siding

22 Signal Ground Signal for 21

23 FPL for 23

24 Signal Ground signal for 25

25 Points Mainline to loop

26 Signal Ground signal for 25

27 Point entry to goods yard

28 Signal Home Branch 2 to mainline

29 Signal Home Branch 2 to loop

30 Signal Home Mainline to platform

31 Signal Home Mainline to loop

32 Signal Home Branch 1 to mainline

33 Signal Home Branch 1 to loop.

B

I am reasonably sure it makes sense overall but have a few slight niggles as follows:

a) Point rodding for one end of crossover (13) needs to go across the rodding for FPL (12)

 

b) Similarly with rodding run for 19 and 21 needing to cross over each other and 23 crossing over 21

 

c) Is the run for 25 and 26 the most likely or would it have been run a long the platform face?

 

I have included a layout plan from Templot and have tried to make a comprehensible diagram. The RHS of layout is depicted at the top and LHS at the bottom

image.png.4b2d84fcda6a0df6d537809fec637512.png

 

image.png.83d4ac971df890e94ce88d1b34c337ce.png

 

Regards

Graham

 

 

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A couple of basic things - firstly all the signal wires would run together as that reduced the number of wire run pulley stakes (and tripping hazards) - look at my photos posted previously).  Individual signal wires can be taken down to a pulley wheel where they change direction to go under point rodding.

 

Drives off rodding runs can go under other rods.  This picture is actually what amounts to a leading;-off bed from a ground frame but look j how a drive is taken to the underside of the middle rod using a stepped leading off crank.

 

1169911308_IMGP6801copy.jpg.5a48985c86a2665f21b3a7e3c21ecb77.jpg

 

884295534_IMGP6801copy.jpg.3fbf03cf6b1e5f9094cda37911890fba.jpg

 

Note in the is picture how the drive is taken off the underside of the further rod to a crank below it in order to drive the point switches.

 

287162035_IMGP6764copy2.jpg.e4ca64a927fb437ec6867d8f7501ccad.jpg

 

 

375811170_IMGP6764copy.jpg.39508eda911fe72a0c9c903f0a43eac2.jpg

 

But rods can be arranged at the leading off bed in a different order from the lever number order if that is more convenient later in the rodding run although usually because the drive is taken from the underside of the rod there is no difficulty taking it below other rods in the run - even with the older pattern of round rodding.

 

The run to the release crossover would be taken immediately adjacent to the platform face as it is out of the way of ground staff in that position and there was sufficient room to do that in real world clerances.

Edited by The Stationmaster
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Thanks Mike

It took me several days to come with a relatively simple diagram to put on the thread. I made all the runs as they would come out of the signal so as to keep the diagram as readable as possible. I will run them all together when I build the layout.

I wasn't sure if running wires and rodding next to platform face would have been the most prototypical. 

One of your previous pictures was very informative as I hadn't considered the need for rollers between the rails. It looks to me that signal wires just lie on top of ballast without any support. Is this correct?

Is the way I have designed my runs within the bounds of what may have occurred?

Best wishes

Graham

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On 29/12/2021 at 07:33, bordercollie said:

It looks to me that signal wires just lie on top of ballast without any support. Is this correct?

When crossing under tracks, yes.  Although if there are track circuits involved something needs to be done to try and prevent the wires touching both rails at the same time!  No impact on a model though.

Running along the track they are supposed to be elevated to stop them getting caught up in vegetation or sticking to the ballast when it’s frosty.  Having said that, I remember places where that wasn’t the case!

Not the best of photos, of a preservation era site, but with professional signalling input so likely to be good practice.  Bo’ness in 2013: you can see wire runs in front of the white fence on the left and in the ‘v’ between the footbridge and the mesh fence on the right.

1502579826_211229Boness.JPG.9d1d55225885550892c574049f7ba9fb.JPG

 

Paul.

Edited by 5BarVT
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6 hours ago, bordercollie said:

Thanks Mike

It took me several days to come with a relatively simple diagram to put on the thread. I made all the runs as they would come out of the signal so as to keep the diagram as readable as possible. I will run them all together when I build the layout.

I wasn't sure if running wires and rodding next to platform face would have been the most prototypical. 

One of your previous pictures was very informative as I hadn't considered the need for rollers between the rails. It looks to me that signal wires just lie on top of ballast without any support. Is this correct?

Is the way I have designed my runs within the bounds of what may have occurred?

Best wishes

Graham

Rodding runs and signal wires ran along the platform edges because that was where they were most out of the way.  the Western even hada special signal wire run pulley assemby for use on brickwork and i think the maximum number of wires these could accommodate was c. 4 or 5 with different assemblies for smaller numbers of wires.  There are still one or two on a brick platform face wall at Swindon - where semaphore signals ceased to exist c.50 years ago.

 

Rodding runs weren't normally put in the 6foot for safety reasons but clearly there were occasions when that had to be done and they were likely to be boarded over where staff regularly needed to work or walk.

 

The western used a special low profile rodding run roller where rods passed under track - as can be seen in one of my photos above .  Signal wires were sometimes run through the articulated type of wire run roller assembly (attached to sleepers) when passing under track to keep them clear of rails but normally the pulleys at the side of the track were set low enough too keep the wires clear of contact with the rails.

 

Don't forget too that the GWR and WR put a hinged steel cover over the facing point lock bolt assembly and final cranks - these began to disappear in the 1970s and were probably removed to simplify maintenance attention.  There is an example  (on a heritage railway) of a GWR pattern cover in my most recent posting above.

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Rodding in modern practice is the square profile (inverted U) seen in photos above. 

 

Don't know when square became standard, but in earlier days round rodding was used by most if not all companies, some of it may have survived to the era you're modelling.  Seemed to persist longer for level crossings worked by gatewheel 

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2 hours ago, Michael Hodgson said:

Rodding in modern practice is the square profile (inverted U) seen in photos above. 

I think of channel rodding (the “square” stuff) as a BR invention of the 50’s but that may be just my perception from when it was imposed/introduced on the WR.  I hasten to add that I wasn’t there for a further 20 years so have no concrete knowledge.

What I did pick up though is that channel rodding is 18’ long so the rollers are at 9’ spacing whereas GWR round rodding was 16’ long with 8’ roller spacing.
Paul.

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Photos suggest that the GWR might well have been installing channel rodding in the late 1930s.  But round rodding survived in everyday useand was fairly common on the WR (and elsewhere, particylarly the SR) well into the 1960s and unlike some other Regions the WR always used round rodding where rods crossed through trackwork installing it in that way into the 1980s whereas some Regions were using channel rodding for that purpose.   A GWR layout set c.1929 would inevitably have been equipped with round rodding.

 

The one thing I'm niot sure about is what was used for the rodding stools the things on which the roller assemblies sit (note the roller assemblies are frequently incorrectly called 'rodding stools' which they very definitely are not). I suspect that the GWR was using concrete rodding stools before WWII but I 'm far from si ure wityhout looking closely at various photos what they used before then.   Simiarly the Western also used concrete beds on which to sit steel plates or straps carrying cranks and these might also predate WWII but again without checking photos I'm far from certain that was definitely the case.

 

PS WR channel rodding was a slightly different size from the BR standard version and the rodding run roller assemblies were totally different and used slightly different size rollers.  It is possible to use WR rodding with standard roller assemblies but I am not sure if it can be done the other way round

Edited by The Stationmaster
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15 hours ago, 5BarVT said:

I think of channel rodding (the “square” stuff) as a BR invention of the 50’s but that may be just my perception from when it was imposed/introduced on the WR.

It certainly appeared in the Tweedie and Lascelles book Modern Railway Signalling which appeared in the 1920s. I think Crewe may even have been 'rolling their own' in LNWR days. 

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Back to signal wire runs on platform faces: this is Worcester Shrub Hill with a seven wire run along the face of the Up platform

2024776846_211230PlatWireRun.JPG.1b2341e0268fcf11bae37aa5321e132c.JPG

 

 

and the seven signals they operate.  (The one in the background isn’t there now!)

1999881420_211230WOSSignals.JPG.6c11afc4f63c86dffb3ba73183e3a98f.JPG

 

 

Paul.

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On 29/12/2021 at 13:53, The Stationmaster said:

Don't forget too that the GWR and WR put a hinged steel cover over the facing point lock bolt assembly and final cranks - these began to disappear in the 1970s and were probably removed to simplify maintenance attention.

One I took at Bearley Junction in 1981

1254614264_110_2-16_1981_bearleyjcn_(800).jpg.074c2b7af4c99a166754701c673b519c.jpg

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Square rodding introduced 1932 according to an official blueprint in my possession.

Of interest - as Mike has mentioned it, here is the round rodding at Blue Anchor in 1975.

1872651476_BlueAnchor26-10-1975Zenit45-(6).jpg.3fa688a1227c17a52c4a9b31d349067c.jpg

1185786380_BlueAnchor26-10-1975Zenit45-(2).jpg.d6dfd6b5c3cb87737d0b905b5d83b04e.jpg

Captain Kernow holding the Up starter off!

149606104_BlueAnchor26-10-1975Zenit45-(1).jpg.a9a91087ebbb4dfcb817329c48079138.jpg

 

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18 hours ago, The Stationmaster said:

Simiarly the Western also used concrete beds on which to sit steel plates or straps carrying cranks and these might also predate WWII but again without checking photos I'm far from certain that was definitely the case.

 

Unless you have the steel plates etc there is a problem as timber slowly decays, the rodding & cranks can exert a lot of force on the coach screws  holding them down.  The Pway should be checking the condition of this of course, but the steelwork means it should be longer before they need to replace the wood. Concrete stools are better, but they still need to be locked in place by ballast - when you pull the lever you want the point to move, not the whole crank assembly or rollers!

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16 hours ago, Michael Hodgson said:

Unless you have the steel plates etc there is a problem as timber slowly decays, the rodding & cranks can exert a lot of force on the coach screws  holding them down.  The Pway should be checking the condition of this of course, but the steelwork means it should be longer before they need to replace the wood. Concrete stools are better, but they still need to be locked in place by ballast - when you pull the lever you want the point to move, not the whole crank assembly or rollers!

Interesting to note in the photos that Tim V has posted that the rodding run rollers are mounted on concrete stools and that these are also shown on the blueprint which indicates that concrete was in use for GWR rodding stools in the days of channel rodding (but not necessarily how early).  the blueprint also shows compensator cranks mounted on steel (or iron?) plate but more significantly the plate is attached to what appear to be the standard Reading design of concrete bed so it too an be dated to be as least as early as 1932.

 

Looking quickly through Noodle Books 'Great Western Infrastructure 1922- 1934 etc. there are photos which clearly show concrete rodding stools in use in 1927, 28, and newly laid in with concrete beds for mounting a plate carrying a crank in 1929 (all with round rodding, including the 1929 job).  All in all an excellent reference source for anybody looking at modelling GWR infrastructure, including rodding runs, in the inter-war period.  It includes a superb view of Heathfield taken in 1927 shpwinga run of 8 rods (!!) and 7 signal wires in front of/on the face of the platform face wall.

 

Reading changed the design of point rodding stools - probably in order to ensure they were better anchored - and that was possibly done post-war.  They were of what amounted, in section, to an exaggerated 'I' shape so had a 'foot' then a narrow vertical area which enabled them to be packed from both sides in the direction in which the rods moved through the rollers.  The top of these stools looked a bit different from the design shown in the blueprint above and they had pre-cast holes which made it very easy to bolt the roller assembly to them.   Very easy to put together even with secondhand material asd I foiund on a couple of preservation sites when laying in rodding runs.

 

16 hours ago, Michael Hodgson said:

Unless you have the steel plates etc there is a problem as timber slowly decays, the rodding & cranks can exert a lot of force on the coach screws  holding them down.  The Pway should be checking the condition of this of course, but the steelwork means it should be longer before they need to replace the wood. Concrete stools are better, but they still need to be locked in place by ballast - when you pull the lever you want the point to move, not the whole crank assembly or rollers!

A friend and I had a visit round a number of 'boxes in the Readng area shortly before the introduction of Reading MAS and there was a rodding run at Reading West Jcn laid on concrete stools and beds but it was right at the top of an embankment and had 'loosened' considerably over the years so you could actually see parts of it (not just the rods) moving when levers were operated - very heavy to work but not the heaviest I ever came across where that ward has to go to an FPL lever at Walnut Tree jcn when the point it bolted became a facing crossover and the lever then worked the FPL at both ends.  My Signalmen were playing merry h*ll about it so I went to the 'box and got the inevitable 'then you bl**dy well try it if you think it is alright' and it very definitely wasn't alright - it took the S&T over a week to get it right. 

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