Insulator Collecting UK — Teleramics

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The Knob!

Key distinguishing points

knob type insulator cross section
  • Spindle usually threaded
  • No inner shed
  • Single wire groove
  • Sometimes known as India pattern
  • Or possibly E.I.560 by Bullers

This particular insulator came from a large redundant hump marshalling yard, Severn Tunnel Junction, and was probably used for short runs across the yard in conjunction with shunter to yard control communication.


This example is one of only three complete examples within the collection.

It is impressed with the Bullers logo and dated 1940 and measures 3.5" high and a maximum girth of 2.25".

Internally threaded and with a narrow wire groove, possibly for 11 gauge wire.


The top has a large 'V' formed into it, its purpose is not clear but possibly it was used in part of the insulator to wire interface, maybe looped around the groove and over the top 'V' notch.

The two remaining examples are again both impressed with the Bullers Logo and dated 1940 and 1944.

insulator fragment

This next view is an part of an example also obtained from Severn Tunnel Junction.

Identical in size, this one is stamped 'BR', (British Railways), on one top face and diametrically opposite stamped with the Bullers Logo, undated.

British Railways did not officially exist until 1948 therefore placing this specimen on or after that date. It may well have been a replacement for a broken, earlier insulator.

insulator fragment

This black variant came from the Burton-on-Trent to Derby line via Egginton Junction, Ex Great Northern Railway, (GNR).

I do not think its of GNR origin though, more likely late British Railways or even GPO. It has no markings at all and is heavily damaged probably from frost.