Several early New England Power Co. 66 Kv (now 69 KV) lines used large 3 and 4 part porcelain pin-type insulators I call "Porcelain 701's" because they are so similar in size to the CD-331 Pyrex 701. Several styles were used on all these lines and they are Sim-M-4330 (Locke), M-4337 (late 1940's Ohio Brass), M-4323 (1910's Ohio Brass), M-4327 (late 1920's Locke), M-3536 (late 1910's to early 1920's Ohio Brass), M-3620 (1920's to 1930's Ohio Brass), M-3541 (late 1920's Locke) and M-4425 1907-1917 Victor). Several other styles much less common were used on different lines and will be discussed later. The M-numbers referred to in this article are from the book Multipart Porcelain Insulators published in 1988 by Elton Gish. The following illustrations from that book are reprinted here with permission of the author.

My real fascination for these big 69 Kv multipart porcelain insulators began on July 20, 1987. It was an overcast summer afternoon, and a friend and I decided to hike an old 69 Kv line about 10 miles west of here. We hiked several towers to find lots of original M-4425's of speckled, rusty, reddish-brown color with the marking VICTOR R=oo so typical of Locke 1910's. We also saw seven more common styles. These sat, still in use, on ancient two-leg pig-iron towers made by American Bridge Co. This line is the C3-D4 line, a two- circuit line built about 1911. I would hike this line in July, 1987, August, 1988, and March, 1989 only to find about six mint M-4323's, very common on this line. These were very early replacements of the M-4425. There are still several hundred original M-4425's still in use after 78 years of service. The line used to tie together several hydroelectric plants in the Connecticut River valley. I also saw several insulators similar to M-3622 and one similar to M-4432.

8/30/87 - Typical C3-D4 line tower with two 
M-4425's, three M-4323's, and a M-3620.

In April, 1988, I discovered in Central Massachusetts an old 69 Kv tap line (14 miles long) with large multiparts that were no longer used. They were long abandoned and disconnected from service. The right-of- way was overgrown with heavy brush and young trees. I call this "the jungle line." The line was built in 1912 and used M-4425's on bow-and-arrow type construction using angle iron crossarms on wooden poles. This line was updated in the 1930's using pin-type, sailboat construction using 16 foot 5 x 5 wooden arms and long 3 x 3 wooden braces and steel static wire. No M-4425's were found in use on these newer poles, but I did find the usual replacements along with M-3541's and M-3620's with a steel clamp-top rather than the usual tie-top. All the M-3620 clamp-top's I saw (except 3) had O-B sandblast markings with 1939 date. They were in a variety of colors. The other three were chocolate brown with O-B marking and 1941 date. This 1941 O-B was the only porcelain "701" I ever found with a regular 1-3/8" pin hole. Every other large multipart I have seen had a 5/8" or 7/8" metal thimble for use with a threaded bolt and cone-shaped steel base for support. There were two CD-331 Pyrex 701's on this line, both having been removed by me in 1988.

8/26/89 - Two M-3536's and a Sim-M-4330
on the discontinued tap line.

In the Spring and Summer of 1989, several collector friends and I removed quite a few multiparts off this line. This was a lot of fun and very hard work carrying these 40 to 60 pound insulators through heavy jungle back to the car in 80 to 90 degree heat. The colors we found in the earlier O-B styles were endless. The only marked O-B's found were the clamp-top and two M-3536's with an embossed O-B marking. The M-4337's are chocolate brown with O-B's SBT marking and sandblasted 47, 48 and 49 dates. The M-3541, M-4327 and Sim-M-4330's were mostly shades of red-brown with greyish tint. The M-3541's had LOCKE R=oo markings. The Sim-M-4330 had LOCKE/V-30 or V-31 marking while the M-4327 had LOCKE R=oo marking or LOCKE/28 V and date (month-year) stamped either on the top rest or marked near the logo LOCKE R=oo. 

2/26/89 - A1-B2 line with one CD-331 Pyrex 701
in service and five O-B M-4337's.

On February 18, 1989, I started hiking the third major 69 Kv multipart porcelain line. The A1-B2 line is the oldest line in the system built between 1907 and 1908 and put into service in 1909. This line connects with the C3-D4 line. It was supplied by four hydroelectric plants and goes through north central Massachusetts supplying electricity to that area, especially the industrial city of Worcester. This line is a two-circuit line built on lattice-type, four-leg towers made by Carnegie Steel of that era. The construction was double triangular with a static wire between the two circuits on a higher steel mast. 

The original insulators used were M-4425's of light tan-brown to mahogany-brown and incuse marked VICTOR. All but a few of these have long been replaced by the same typical multiparts found on the preceding line along with an occasional CD-331 Pyrex 701 which I saw two still in use along with a slightly damaged one. I found lots of pieces of the original M-4425's near towers on this line, but nothing close to collectible. The line was upgraded to a larger size conductor in 1919, and I estimated by then, much of the original insulators failed in service due to cement expansion, lightning puncture or weather cracking. This line has had severe problems with lightning, and about 30% of it now has replacement post-type insulators of recent manufacture. I did find several unusual styles on this line, and all of them have been isolated and scattered. I did see two M-4700's on a tower which is one of the largest (88 Kv) pin-type insulators I have ever seen. These are just incredible with combination mottled tan and dark grey colored skirts, probably of O-B manufacture. I did see a Sim-M-4326A and M-4432 both in chocolate brown. This line has a good assortment of the more common styles, and the M-3536 and M-4327 seem to be the most common. Some of the Locke's I saw had a nice grey color to them. I also saw two M-3541 clamp-tops in red-brown and one M-3620 clamp-top still in use on this line. I managed to find a mint Sim-M-4330, M-4337, M-4327, and M-3536 on this line in February and March, 1989.

2/18/89 - Transposition tower on the A1-B2
 line with three M-4327's, two
M-3536's and one M-4330.

4/29/89 - The W-23 line with one
M-3536 (right), one M-4337 (top),
 and one original M-4425 (left).

There were several shorter lines with multiparts. I saw a few porcelain "701's" along with 21 Pyrex 701's on the S-19 line (1916, wooden poles, triangular construction) in central Massachusetts in March, 1987. Other lines of these are L-38, M-39, N-40 lines (all 1910) of A1-B2 line type construction, and W-23 line (1917, wooden pole, triangular construction with angle iron crossarms). I saw a few Locke and O-B clamp-tops on the L-39 line, and about 15 original M-4425's on the W-23 line. It is interesting to note that I found pieces of M-4425's on every 69 Kv pin-type line I have hiked. My interpretation is that M-4425 was the standard insulator for new construction while all the other styles were replacements over the years. This might not have been 100% true of the S-19 and W-23 lines since the replacement M-4323 and M-3536 were introduced by the time the lines were built. All 69 Kv lines built after this period were suspension lines on this system.

In conclusion, this is all I have seen of early multipart porcelain insulators in use in the early 69 Kv (originally 66 Kv) circuits of the New England Power system. This was over 100 miles of hiking and research of these lines. Several other lines of these existed, but were either changed out entirely or dismantled. My biggest dream when hiking these porcelain "701" lines was to find a mint M-4425.

On October 1, 1989, a gorgeous foliage-filled, sunny day, my friend, Joe Maurath, and I were hiking C3-D4 lines looking in awe at those beautiful M-4425's in service. We both talked and fantasized about getting one of these. I wanted one in the worst way. We came to an abandoned power line phone shack on this line. Joe took a picture of a nearby tower while I went in. I almost went into shock. There sat my dream piece along with a M-4323 and three M-4337's. My dream M-4425 was MINT, with an orangey, speckled-brown color, and with the 1908-1922 era marking VICTOR R=oo. This was my proudest moment in collecting these big 69 Kv multiparts. I once again screamed that triumphant joy driving down the road! The wonders in this great insulator hobby never cease!

10/1/89 - Mr. 701 holding his dream M-4425 
moments after finding it in an old abandoned 
transmission line phone shack.