Having worked for an electric utility company for 37 years, the word "underground" compels me to write about one thing – the electric subway system.

As early as my first week as a field mapper, I learned a little about utility construction. My senior coworker and I drove around the city inspecting various sites where construction crews were building new manholes.

At our first stop, a crew had dug a large rectangular opening in the road. The backhoe had exposed an old trolley track about 18" below grade.

Next, we witnessed another crew installing wooden forms as if they were building a small house under the pavement. Once they completed the carpentry, the structure was ready for the concrete. After the concrete had cured, the crew removed the forms.

Then I could enter the underground structure and take measurements. Since the crew had recently pulled the forms out, I could feel the warmth of the exothermic reaction of the curing concrete. Generally, a hole's dimensions were 8' wide by 10' to 14' long and 7' high. I could be off a little since it's been a while since I've even thought about the details, but that's a general idea.

The ceiling and walls are about a foot thick. The top of the boxlike structure is usually about 30" below the final grade of the road. A round brick "chimney" is built as an entranceway from the round steel cover on the street to the manhole below. I remember watching a bricklayer construct a chimney. It was an impressive experience. A good bricklayer could split a brick perfectly in half with one gentle tap of the handle of his trowel – amazing! A true craftsman.

I said that most manholes are generally the same size. But there are plenty of exceptions. Sometimes a wall has to be made to fit around an obstruction like a sewer line or another manhole, resulting in a slight polygon shape. Sometimes the neck, or entrance, is deeper than 30". I remember climbing through an entrance that must have been at least 5' deep, barely enough room to lean a ladder. Since the width of the entrance is only 36" in diameter, there would be a maximum point of depth where a person would not fit through the chimney with a ladder leaning to the side.

Then there was the gigantic manhole. It was part of a massive electric substation complex. So, there were plenty of cables and conduits going in all directions. The structure was bigger than a good-sized living room. All the underground guys referred to it as "The Ballroom."

One day, I was taking field notes inside a utility box that wasn't much larger than a casket. The cable crew I was with decided to close the cover on me as a prank. Little did they know I was very comfortable being inside the tiny structure. I didn't mind at all, even though it was pitch dark. It felt quiet and relaxing... for a moment.

Copyright © 2023 by Michael DeFrancesco

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