In the March 1996 “Porcelain Insulator News”, we discussed incuse MP markings on U-152 and U-610A. This marking is uncommon on U-152 and rare on U-610A. A number of unmarked U-152’s were reported in April 1996 Rainbow Riders to have been found on an extension of the Missouri Pacific railroad line into northern Louisiana. Patrick Scott sent me a letter giving more information on the elusive MP insulators.

Patrick said that he has been collecting MP insulators for nearly ten years, and furnished some details about his searches. In April 1995, the Union Pacific dismantled part of the signal lines in and near Cahokia, IL on what is known as the Chester Subdivision. He retrieved a number of the MP marked U-152’s many of which were white. So far this is the only location he has seen where white insulators were used extensively. The purpose of the white U-152’s was to support the 600 volt power line at the end of the crossarm. Elsewhere on the Missouri Pacific railroad this power line is supported by various glass and porcelain cable insulators. At least that is Patrick’s observation from traveling through Missouri, Kansas, Illinois, and Arkansas. The brown U-152 MP insulators were used much more often than the white U-152 insulators — sometimes ten per pole. Patrick said he has heard that the Union Pacific will be removing the remaining part of this line near St. Louis. This line has a good number of white and brown U-152’s some of which may be marked.

Patrick has only seen about seven U-610A’s with MP marking. He recently found three on the Union Pacific lines near St. Louis and two more a month after that. He says many of the U-610A’s which appear to be MP’s turn out to be unmarked. There were also many areas where the U-610A (two per pole) were replaced with Hemingray 660. All this contributes to the difficulty in locating a U-610A with the incuse MP marking. I have counted nine U-610A in collections which are known to have the incuse MP marking. Fairly rare indeed.

Patrick reports one other very interesting item. On one of his recent hunts for the MP insulators, he found four brown U-610A insulators with the incuse “G. P. Co.” marking as well as one brown U-625B with that same marking. So, maybe an MP marked U-625B will someday show up. The U-610A with “G. P. Co.” marking Patrick sent me has nearly the identical glaze as the MP marked one I have (odd chocolate with a multitude of darker specs). This is further proof that G. P. Co. made the MP insulators (remember the U-152 reported in March 1996 Crown Jewels of the Wire with both markings?). Thanks Patrick for the interesting background information on the MP insulators.

The following two photographs illustrate the variation in the brown-glazed U-152’s with MP marking. It seems the skirt-marked insulators are more scarce than those with the marking on the dome. Unfortunately, you cannot see the dramatic difference in glaze characteristics. The second brown U-152 from the left has a thick, dark chocolate glaze while the other three have a lighter, odd chocolate brown color that I call German Chocolate (you bakers know what I mean). Note the light-colored areas around the edges of the tie-wire groove where the glaze is thin. Likewise, the two white U-152’s pictured are different, too. The one on the right is finely made, and the one on the left has a crude appearance with a bumpy surface and many dark specs in the glaze. I don’t know if any of the white U-152’s have been found with the MP marking on the skirt.

Brown U-152's with incuse MP marking. Two on the left are marked
on the skirt and the two on the right are marked on the dome.

White U-152's with incuse
MP marking on the dome.

George Nowacki (NIA #5813) has been finding several unmarked Fred Locke M-3060’s along an old line in Ontario in the copper mining district near Sudbury. These have the characteristic pretty tan glaze with some mottling that is greenish in color. A large heavy U-shaped metal pin was cemented in each. George has recently found a few more nice ones that he has available for those interested. He sent me photographs of another M-3060 which was found along this same line by a friend (buried four feet down). This insulator has a weak but recognizable #7-1 Fred Locke marking!! This confirms that all the unmarked ones are also Fred Locke insulators. Most likely the bulk of the insulators used on this line were made shortly after Fred Locke left the company in late 1904 as evidenced by so many unmarked specimens. I just got word from George that he has finally found a M-3060 along the line with the #7-1 Fred Locke marking!! Now he doesn’t have to drool over the one his friend has, and who refuses to part with it.

M-3060 with 7-date Fred Locke marking. 

The next insulator was reported by Rick Soller (NIA #2958). Rick sent in this super photograph which clearly shows the large flared skirts. (See following page for photo.) I have assigned this M-4345 (14 - 7 - 12 - 10 x 14). It has an embossed O-B marking on the crown which is the logo of the Ohio Brass Co. Besides the very attractive large lily-shell skirts, the glaze color is a beautiful orange-rust characteristic of early (1907-1910) Ohio Brass production about the time they took over the Akron High-Potential Porcelain Co. Rick says that there is an incuse “C” on the underside of the 2nd skirt from the bottom. You really should see this insulator in color, so hopefully, it will be on the insulator web page by the time you read this (http://www.insulators.com). M-4345 was shown on page 179 in Brent Mills book, Porcelain Insulators and How They Grew. It is in the John S. Lapp Insulator Museum at the Lapp factory in LeRoy, NY.

Bill Sutliff (NIA #3223) reported an unmarked Cook M-2616. This was an unreported style in the Value Guide. Bill said he found a few of these on a pole that was blown over during a storm. He said that the insulators on this pole evidently escaped being changed out many years ago because it was in the middle of a swampy area and the no other poles had this style of insulator. Note the characteristic Cook crown in the patent drawings and catalog illustration (all shown in my book Multipart Porcelain Insulators). The cable groove is slanted on the ends and the tie-wire groove is sloped up toward the conductor groove. These features were claimed in W. S. Cook’s patent No. 1,688,411 granted on October 23, 1928.

M-4345 made by Ohio Brass circa 1907-1910. (14 - 7 - 12 - 10 x 14)

M-2616 unmarked Cook