Jon;
Railroad jargon has one other use for boomer. A “boomer” was a railroader who was always moving his/her employment to a railroad that was “booming” (that is, prosperous) there was no company loyalty. I remember reading a story in the old Railroad magazine about a boomer lightening slinger (telegrapher). Boomers were resented by the “home guard” (railroaders who stayed with the same railroad).
Best, David Meashey