"Am I correct in remembering that Harriman commutes had double windows
and that "long hauls" had single windows? Because of seating?
Both models represented at Sacramento, properly identified?"

No, the 96 seat commute cars which lasted in SP service until 1985 had single windows too. You are thinking of the original 60 foot steel cars, about half of which has double windows. They seated 72. The last of those were retired in 1968.


"Does the current public schedule show all of the evening expresses arriving at their first stop at about the same time?"

Caltrain no longer has the rush hour schedule like SP. They don't have the "first stop" every three minute departures. Back in the day they roughly arrived at their first stops around the same time.

From late 1964 to Caltrans, they left between 5:14 and 5:26 with first stops at California Ave, Redwood City, Belmont, Burlingame and South San Francisco.

From about 1957 to 1964 there we seven of them, with trains making first stops at Menlo Park and Millbrae, in addition to the five above.

Before 1957 there was an 8th train on the 3-minute fleet which made its first stop at Atherton.

There was some variation in earlier years. The second to last made its first stop at Broadway, rather than Millbrae; the Belmont first stop was Hillsdale instead, etc.