Ed you are correct in the fact that most of the els on tank car expansion domes were street ells but these were not used with the heater coils. The safety vent or valve was screwed into the female end. Jeff Coleman
--- In STMFC@yahoogroups.com, "ed_mines" <ed_mines@...> wrote:
I think those plumbing fixtures coming out of the sides of older
tank
cars domes are street els (short for elbow).
They are threaded on the outside on one end and on the inside of the other end.
I think they were used to put steam into heater coils or the tank itself.
It was easier to replace this kind of fitting if the threads were damaged.
