Railway telegraph poles - how many are left...and in use?

JamesT said:

Inside a property I’ve certainly seen Openreach using jelly crimps to connect two cables. I would expect some sort of connector box would be the preferred route over solder or twisting together for a reliable connection.

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Jelly crimps are relatively modern to the railways. They are used by the telecoms part of the railway. They can be used in enclosures, dis boxes, location cupboards and similar places, as well as in buildings.

Although in most enclosures and location cupboards, fixed terminals are more common. For example, Krone IDC terminals were common in the past in the area where I worked.
Like this example:


(linked photo shows a IDC - insulation-displacement contact terminal block, also known as a punch down block, this example being a Krone type)

Krone type mount on metal back plates and can accommodate one 10 pair cable.

Other high density connectors are available from other manufacturers.

Of course, poles, and all associated location cupboards and dis boxes will use much older terminal designs.

Re the NYMR.
There is a pole route between Newtondale Halt and about the 14 MP.
The route up to the 14mp is then through the forest.
I think it is in use for the emergency phone at the Halt.

Annetts key said:

Jelly crimps are relatively modern to the railways. They are used by the telecoms part of the railway. They can be used in enclosures, dis boxes, location cupboards and similar places, as well as in buildings.

Although in most enclosures and location cupboards, fixed terminals are more common. For example, Krone IDC terminals were common in the past in the area where I worked.


Of course, poles, and all associated location cupboards and dis boxes will use much older terminal designs.

Click to expand...

I doubt that you would want to use a jelly crimp or any other form of IDC connector on a wire that is under tension, as they cut into the conductor and so inherently must weaken it.

While screw terminal type connectors (such as 0BA and 2BA terminals) were common in signalling circuits, telecomms don't like them, as they are a common source of noise. Hence their move to IDC type connectors.

On a pole route, where the route transitions to cable, a special terminal pole is used, which is stayed and has cross bars designed to counteract the pull due to their being spans on one side only. Each overhead wire is mechanically terminated on its insulator by twisting it back on itself. The electrical connection to the drop wire is then made by twisting it around the overhead wire. That way the joint is not under tension. There is then usually a disconnection box at the bottom of the pole where the connection is made between the individual drop wires and a multi core trackside cable.

I should also perhaps explain that the kind of twist joints used are not the same as sometimes used in electrical engineering practice, such as when putting two wires into a terminal in a socket. These kinds of joints quickly unravel if you pull them. The kind of twist joints used with overhead wires are more alike how you splice two ropes together. The two wires are held parallel to each other, with the cut ends facing in opposite directions, and then twisted together. Hard to describe in words, but a quick search for Britannia Joint will show it.

My text book says that in America it was common practice to leave sufficient extra cut end either side of the twisted joint so that you could fold them back in parallel with the main joint and solder them together, rather than solder the main joint. So you had a soldered electrical joint in parallel with the twisted mechanical joint. If you don't do the soldering correctly, you can overheat the wires and weaken them, so by not soldering the main joint you avoided this risk.

== Doublepost prevention - post automatically merged: 20 Jul 2026 ==

Dave S 56F said:

The keighley worth valley railway still have em with wires on and used as well as the bells can be heard ringing on all six stations when the steam train is due incoming. I think as well the N.Y.M.R. has telegraph poles as well with wire on em if there still used I'm not sure as all the stations between pickering Grosmont barring newtondale are mechanically signalled.

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I thought the NYMR had transferred their token instruments and bells off the overhead wires to data connections through t'internet?

I think it should be remembered that the wires on the poles were a lot bigger than the small stuff used for telephone circuits to domestic properties. They weren't measured by diameter but by poundage. So you'd take a block of copper, stretch it for a mile and that's the final size. The normal ground level cable conductor size prior to modern poly insulated stuff was usually 20 or 40lb, I have worked on 70lb stuff but that was hard work. The open copper on poles could be anything from 150lb upwards so hefty stuff.

One of the last operational pole routes in Great Britain was on the Breckland Line and ran intermittently between Brandon and Wymondham. This was an exceptionally late survivor and was taken out of service in 2008. Some more held on up near Elgin in Scotland but I am not sure of their current status.

Pole Route's really were an artform, each pair of wires would cross eachother in transposition every so often to ensure that they did not interfere with eachother, and the top two wires would often carry 110VAC on open wires with red insulators. They were a real maintenenance liability, which were easily replaced with the advent of multi core cables. In high winds the swaying of the wires would cause all kind of mayhem with the block circuitry, with the needles swinging violently between states and the block bell ringing intermittently.

I remember the winter of 1982 when mile upon mile of overhead pole route came down due to the weight of snow on the wires. I'm pretty sure it was around the Yeovil area. Copper everywhere and snapped poles strewn around. We used every bit of interruption cable we had laid on the ground to replace the wires. No fun jointing it in the cold.

Taunton said:

As there is still quite a lot of traditional block working around, how are bell codes transmitted if not by telegraph line?

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I think it's often the case that the electro-mechanical block instruments are actually triggered by data transmitted on much more digital telecoms systems. So fibreoptic cabling carrying multiplexed TCP/IP just like the Internet, but actually it's all for ringing a bell. I have no idea what the equipment is like that bridges those two mediums

== Doublepost prevention - post automatically merged: 21 Jul 2026 ==

Mechy said:

One of the last operational pole routes in Great Britain was on the Breckland Line and ran intermittently between Brandon and Wymondham. This was an exceptionally late survivor and was taken out of service in 2008.

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How interesting, what did they do? - I think that line had been fully re-signalled to Cambridge PSB for a while before than

GraphitProjekt said:

I think it's often the case that the electro-mechanical block instruments are actually triggered by data transmitted on much more digital telecoms systems. So fibreoptic cabling carrying multiplexed TCP/IP just like the Internet, but actually it's all for ringing a bell. I have no idea what the equipment is like that bridges those two mediums

== Doublepost prevention - post automatically merged: 21 Jul 2026 ==


How interesting, what did they do? - I think that line had been fully re-signalled to Cambridge PSB for a while before than

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Block bell circuits are usually just a voltage applied across a core of a multi core cable. Nothing fancy, just a voltage that drives a relay at each end operated by the tapper on the block instrument.

The Breckland line was still under semaphores in 2008. The pole route was moved in to line side multi core cables in that year and the resignalling to Cambridge took place in 2012. The pole route carried all of the block circuits, local signal controls/indications and telephone circuits. The circuit phone remained operational right until the pole route came out.

One of my jobs on the railway was to plan the cable routes that replaced overhead pole routes. This included everything west of Carmarthen, Ludlow to Craven Arms and beyond, plus the Rhymney Valley. The new signalling and telephone cables were buried using a mole plough train except where rock, bridges or other factors dictated concrete troughing. A lovely time was spent surveying each section, followed by installation drawing production and material ordering lists. Not such a lovely time though on the overnight mole plough train itself when it was frosty and everything was icy. Not sure it would be permitted these days.

GraphitProjekt said:

I think it's often the case that the electro-mechanical block instruments are actually triggered by data transmitted on much more digital telecoms systems. So fibreoptic cabling carrying multiplexed TCP/IP just like the Internet, but actually it's all for ringing a bell. I have no idea what the equipment is like that bridges those two mediums

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Well, before telecommunications systems switched to their modern digital network system, exchanges and transmission systems (including the old 4MHz frequency division multiplex transmission carrier systems and 1980s technology fibre optic transmission systems) often supported E&M signalling, for details read the Wikipedia article.

I doubt that a safety critical block circuit would be permitted, but block bell, emergency alarms and other non-safely circuits were carried over these systems in the past in my former area.

The railway also used "private" wire connections provided by BT in the past, they could be used for DC signalling.

Some of these in more recent times could only be used for audio frequency transmissions, so Reed FDM systems were used. If a safety critical reed FDM system was used, they could carry block circuits and token circuits etc. For these circuits, BT provided a "network termination unit" (at least I think that's what they called it), it has a two line backlit LCD display to show the status.

Hellzapoppin said:

I remember the winter of 1982 when mile upon mile of overhead pole route came down due to the weight of snow on the wires. I'm pretty sure it was around the Yeovil area. Copper everywhere and snapped poles strewn around. We used every bit of interruption cable we had laid on the ground to replace the wires. No fun jointing it in the cold.

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Something similar happened north of Inverness leading to the Radio Block system where the existing tablet system communicated via radio prior to the introduction of RETB several years later.

Annetts key said:

Jelly crimps are relatively modern to the railways. They are used by the telecoms part of the railway. They can be used in enclosures, dis boxes, location cupboards and similar places, as well as in buildings.

Although in most enclosures and location cupboards, fixed terminals are more common. For example, Krone IDC terminals were common in the past in the area where I worked.
Like this example:

(linked photo shows a IDC - insulation-displacement contact terminal block, also known as a punch down block, this example being a Krone type)

Krone type mount on metal back plates and can accommodate one 10 pair cable.

Other high density connectors are available from other manufacturers.

Of course, poles, and all associated location cupboards and dis boxes will use much older terminal designs.

Click to expand...

We've used these for our third-generation signalling simulator at the St Albans South signal box:

The photo shows the Krone connectors which are used to link all the instruments, lever position microswitches, bell tappers and the like to several interface boards. There are some 200+ pairs of connections involved. The interface boards are linked by USB connections to a Raspberry Pi, out of sight in the picture. The photo was taken during the installation of the new system.
All the above are hidden behind our track diagram, the back of which can be seen behind my colleague - the diagram is on a large concealed pivot at one end.