So, take it away John!
There was usually no need to wait at E. Haddam unless the first train to arrive was to receive a "hot" car from the second. The Shore Line local received the lion's share of this exchange and often was the reason for the Valley local running down to E. Haddam on other than Tues., Thurs., & Saturday.
In my experience we would run to E. Haddam as well as Berlin on Mondays which created a long day for the crew. Cars from the B&M and NYC exchanged in Springfield were usually preblocked for Hartford and Ceder Hill. Hartford, being a smaller operation, could handle these cars faster than Cedar Hill and usually make the morning run of the Valley Local faster than they could if they were sent to New Haven.
However, as traffic declined in the late '40s the Hartford yard activity began shifting to Cedar Hill. An example of this was the discontinuation of the through trains between Maybrook and Hartford. The cessation of the Hartford/Boston freights after the 1955 flood ended significant classsification activities at Hartford. I know the hump operation at Hartford was closed at some point during these years but I don't know exactly when.
I think your records show that the Valley Local was cut back to 3 days per week in 1949 which was probably why Bill Beaupre bid a Springfield passenger job. He loved the Valley job and I doubt very much that he would have left it unless it became a financial necessity.Certainly on my list of things to do, especially now that layout construction is winding down, is to get a much better understanding of how the locals interacted with each other, how the cars were handled, etc. Fortunately, I have a few RR-produced booklets that give (at least part of) the official plan of operations, but there are plans and then there's reality. And nothing beats the memory of one who was actually there to tell you how things actually worked.
So thank you John - this information goes a long way toward filling in some of the knowledge gaps the RR paperwork leaves behind.