Multipart Porcelain Insulators
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M-2332 (Locke catalog #307, 1-3/8" threads; #307A, 1" threads)
Production dates: 1901
There are three distinct variations of the M-2332. In the 1902 Locke catalog the #307 and #307A are listed as having a diameter of 7-1/2" which corresponds to the left and center specimens. The 1904 Locke catalog has this insulator listed with a diameter of 7-3/8" which is the diameter of the right one. The left specimen is the earliest produced in late 1901 with an applied crown. The blonde specimen in the above photo was produced in 1902-03 and has a full mold line extending from skirt edge to skirt edge. The right specimen has a mold line over the dome and a mold line line or raised ridge circling the crown. This is found on 1903-05 era insulators.
The M-2332 was well documented by long time collector Robert Winkler. According to him, this insulator was the favorite choice of interurban railroad builders in the Midwest from 1902 to 1907 and they were being installed that late. They were once as common as a Hemingray 42 on the early electric railways of the Midwest.
This design was very widely
used on a number of interurban railroads in the Midwest primarily in Ohio,
Indiana, and Illinois. There is historic photographic evidence of another
installation in Connecticut on the Bulls Bridge-Woodbury transmission line built
in 1903, but none have been found there by collectors.
Specimens of M-2332, though
scarce, have surfaced in widely distributed locations in the east with most
coming from flea markets or antique shops.
Some have been found by collectors north of Chicago on an old interurban
right of way.
Two specimens of the #307A were recently
removed from service on a 4 kV line in an older part of St. Louis, MO by a line
crew for collector Pat Scott. One of them
is the only known specimen with an applied crown. It was produced on
December 17, 1901, less that two weeks before fire destroyed the Victor
plant. It may have been in one of the last shipments to leave the
plant. Interestingly, both specimens have 1" pinholes making
them the first reported #307A
specimens. All of
the other known M-2332's have 1-3/8" pinholes #307 as shown in the 1904
Specimens of M-2332 can
have either marking 6-1 or 7-1. At
least four or five unmarked specimens are also known all of which were produced
in either 2-part or 3-part molds.
This design fell out of
favor after about 1905 and most were replaced by styles like the M-3060 produced
by other manufacturers.
two found in St. Louis, MO in 2009 and removed in December 2011. Photo
courtesy of Pat Scott.
M-2335 (Locke catalog #306)
Production date: 1900-1901
The small two spout gutter
was used on a single line that ran from downtown Tacoma, WA paralleling the
American Lake trolley line south of Tacoma.
Only three insulators from this line have survived that were found in the
Tacoma area. One was recovered by a collector and his son in 1967 from an
abandoned pole along the line. These have 1-3/8" pinholes.
A fourth top was found in
the Victor plant and taken home by a long retired employee that later ended up
The markings on these insulators are #4-1 and #4-3.
Parts of a white top were
also found in the Victor plant dump, which had marking #6-2.
M-2335A (Locke catalog #306)
Production date: 1902
Only two known specimens of
this insulator exist. Reportedly they were used in a now long gone substation in
Philipsburg, Montana. Both came from long retired lineman originally and both
have marking 6-1. Both have 1" pinholes.
M-2336 (Locke catalog #304)
Production date: 1900
This insulator was found in
the Victor plant only one specimen is known to exist. It has marking
4-1. On the opposite side is marking VICTOR / APR. 10 1901.
M-2401 (Locke catalog #)
M-2430 (Locke catalog #408A)
Production date: 1903-04
About a dozen marked
specimens of this insulator and 25-30 unmarked specimens were found on a 50-mile
long line 1903 line from the Junction City power plant at Eureka, CA. All marked
specimens had marking 7-1. Two double-marked specimens are also known.
A few broken ones were also
found on a line south of Chicago by Bob Stahr in the 1990's.
This Fred Locke design
became one of the most popular small multipart insulator designs used in North
America. In subsequent years, it was copied and produced by the millions by
nearly every known manufacturer up into the late 1930's.
One marked white glazed top
to a M-2430 was found in the Victor dump and it is the only known white example
of a Fred Locke cemented multipart other then the white M-2795.
M-2785 (Locke catalog #318)
Production date: 1902-1903?
M-2785 is known in collector circles as the big crown gutter, was produced in the years 1902 and possibly 1903. After the December 1901 factory fire, the Locke #318 (formerly M-2796) was completely redesigned to eliminate the weaknesses in the older design previously produced. One new feature was the socket shaped joint where the crown was applied to the body of the top skirt. This eliminated the problem of the crown shearing off under lateral strain that plagued the earlier design. The second feature allowed the upper portion of the collar to be recessed in the body of the top skirt preventing the problem of the collar breaking under lateral strain.
Two different variations of this rare style exist. The one on the left with the smaller collar was found only in Washington state. It was used on the Puget Sound Electric Railway. These were first installed in early 1902 and remained in service when the line voltage was upgraded to 55 kV around 1917. Subsequently a large number of them were reused on two lines. One was a few miles north of Enumclaw, WA and the second line was in a secondary under-build of a 55 kV transmission line which paralleled the Seattle-Everett Interurban Railroad. All of the known specimens of the small collar version were found near Enumclaw, WA. About a dozen exist. One damaged specimen was found on the original line near Milton, WA with marking 1-8. All other known specimens have marking 6-1.
The M-2785 with large collar have been found only in northern California in PG&E territory. They appear to have been originally used on lines constructed in 1902. Most of these were salvaged and used on scattered lines constructed in the 1908-1925 era. Very few of these are known to exist today -- may be 1/2 dozen of these at most. All specimens of this design have applied crowns and marking 6-1.
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