TerryC wrote:What was it like to watch them and/or ride them?
I remember clearly when these units arrived on the property. They were my first experience with new locomotives (whoopie!). They were much nicer to work with than what they replaced (a mixed bag of RSD12s mu'd w/ GP9Bs, RS32s, GP20s, etc.). Selkirk received units 6710 through 6718 (later renumbered 6910 to 6918).
6714 and 6716 were equipped with hump cab signals with three positions -- green for shoving toward the hump, yellow for humping, and red for stop. Signals were controlled by the conductor on the panel up in the hump building.
We used single U23Cs as pullers on the East End of Selkirk to pull cars out of the class yard to make up trains in the departure yards. A double unit set was used on the hump (with pilots trimmed to clear the retarders). Two U23Cs would handle any train the humpers had to shove or pull back. They were used for this purpose until the SD38/MT-6 combos replaced them in the early '80s.
The cabs were very warm in winter, with a heater blower that made very little noise -- a definite improvement over the stuff they replaced. Some ground folks complained they were too warm for times when the brakemen were suited up for the terrible Selkirk blowing cold. We'd just say, "Well -- go back out there, then."
Cabs were painted dark green -- typical for PC units -- changed to light grey in the CR period.