Insulator Collecting UK — Teleramics

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The Terminator

terminator insulator cross section

Key distinguishing points

  • Three main sizes in existance.
  • Known to be made in White, Brown, Red and Black.
  • Used as a termination point.
  • Inner shed length varies dependant upon year of manufacture.
  • Twin wire grooves.
  • Less common than the standard pattern of insulator.

Medium Terminator


Designated by Bullers as the No.7 for the standard sized version, they sit approximately 5" high by 3" diameter.

The smaller version has a designation of No.8 and is 4.25" high by 2.5" diameter.

A much larger version exists measuring 5" high by 3.5" diameter but, at this time, its Bullers number is unknown.

As with standard pattern, the reason for variations in size is not clear.

Again as with the standard pattern older variants have the extended inner shed, certainly by 1956 the inner shed is shorter than the outer shed.


Stamped with the letters NR on the top and LNER on the top front face, this is also believed to be a TTC product, though the meaning of NR and other similar letters on other various insulators is eagerly sought.


A medium sized terminator, clearly marked GWR and with the TTC logo on the rear face this is more slender that other medium sized terminators and possibly of older design.

Several variants exist within the collection, marked either GWR or LMS, with and without the TTC logo.

Small Terminator


Small black terminator. With no makers signature visible it is believed to be from Taylor Tunnicliff. It has the characteristic square shoulder and thin wire ridge typical of similar marked TTC products.


Small type terminator clearly marked GPO on body front with hand logo on rear made by Wade.

Large Terminator


This larger terminator is stamped LNER on the front top face and on other, non LNER versions has the Bullers logo in a similar place. These bullers stamped versions do not, unfortunately, give the date nor model no.

Sinclair Aitken


A two piece terminator known as the Sinclair-Aitken pattern. The centre core is slotted and threaded internally and externally. This allows it to be threaded on to its anchor pin. The lead in wire then passes through the top slot and the cap / outer is screwed over the inner to complete the design.

Obtained from a second hand stall its origin and maker are unknown, though W.Keith Neal states in his book, Searching For Railway Telegraph Insulators, that they were used on the Great Eastern Railway and widely used by the Post Office until the Pot-Head took over.

Sinclair Aitken Terminator pattern drawing - Fredrik Höjefält

Thanks go to Fredrik Höjefält for providing me with this pattern drawing.

It clearly illustrates the method in which this insulator was used, need I say anymore ?

An Early Bullers Large Terminator

Bullers ltd london insulator fragment

This piece appears to be from the top of Large PO pattern terminator. Its size and shape match existing examples of Bullers made terminators held within the collection.

Impressed on to the piece are the words BULLERS Ltd, LONDON, Rd No 2??????'. This fragment dates the registration of the design to between 1885 (Rd No.19756) > 1886 (Rd No.40480) or 1893 (Rd No.205240) > 1897 (Rd No.291241).

Update December 2005

I have found a more complete example which gives the full registration number and I can now date the pattern more accurately

This example is still stamped Bullers Ltd London but in the larger style and the complete registration number reads 271970

According to information obtained from the potteries web site, , this dates it to 1896 (268392 to 291240)

Gaskell & Groucott

large terminator

This large Gaskell and Groucott terminator was part of a larger haul collected over the winter of 2004 to 2005 from the Settle and Carlisle line.

Much lineside tree felling has been undertaken on sections of this line and as a consequence many previously hidden pole remains have come to light

I have left the original wire fixing on this example as a record to the way the it was terminated.

G&G logo

Each example has the Gaskell and Groucott insulator and catch phrase logo impressed on the top slope.

This computer altered image helps to see the catch phrase, The Only Way G&G England over a double shedded insulator with wire

Latest find


This mystery insulator came from the West Coast Main Line near Penrith and is obviously a terminator insulator but unlike all other examples I have it is of bright white porcelain and of a different profile, all be it slight, but to me it must be from a different manufacturer or an early example.

There are no internal or external markings, the walls of the sheds are quite thin and the inner shed protrudes more than usual, 3/8 inch compared to the usual 1/4 inch.

The base is glazed suggesting it was fired upside down, though none of the top remains to confirm this.

These facts together with very droopy shoulders leads me to believe this may be an early insulator from Bullers, probably pre 1900

Latest Addition

large red insulator

Thanks go to Tris Horton for very generously donating this Large Red Terminator to the collection

This insulator is in mint condition and an excellent example of a rare railway insulator designated for power as distinct from telegraph use

It has a lovely 1949 dated Bullers stamp in the front of the outer shed

As with most Bullers insulators, it has been fired upside down hence the white, unglazed top. Further examination inside the soot stained underneath reveals the depth to which the red glaze has reached, all the way down to the thread.

The colour is not an accurate rendition, the true colour being much a darker and deeper red, though