This is one of the weirdest most useless pin types ever put on a power pole . It has ridges like a Mershon CD 288 that are so small they would not alter the direction of a raindrop, A crown so small it could easily brake off and a 1-3/8" pinhole that makes the inner skirts prone to snapping off . Wile most imperial insulators are of very conventional design, This one stands out as the rare oddball. This insulator was, insofar as anybody knows, used only on a short 3 phase feeder circuit for a trolley line in the area of Worcester, Mass. that powered an ac-dc rotary converter .The line was abandoned in 1927. Only three complete specimens exist in the hobby today. These are only marked " Manufactured by Imperial Porcelain Works, Trenton N. J." using the later stamp seen with the crown marking on other Imperial products. The U-938 lacks the usual crown marking and manufacturing date seen on most imperials.

It is well known that C. S .Knowells was a distributor and jobber of Imperial Porcelain products in the 1900-1904 era . The U-938's similarity to the glass styles with braces under the skirt would lend credence to the idea that Knowells had this design produced for their own sales to go along with the various Novelty Glass products they were selling at the time. According to a 1902 article in "Street Railway Review" the line of the Worchester and Southbridge Street Railway was 20 miles long . The insulators were specified as brown porcelain with large petticoats supplied by C.S.Knowells . The voltage was 11kv and the pole construction was for two circuits but only one was installed with insulators. The line was built in 1902 and served as a mostly passenger only line with little freight service. Most of the line rout is now urbanized and no longer exists and a few sections have been turned into a bike trail. There is only a very remote chance any more of these will be found. To see what the line looked like[id=151373389]