I noticed on a subway track map that the 57th/7th station on the Broadway Line has a pair of crossovers between the express tracks both just South of the station, and just North of the station. Of course, I already know that every bit of train movement costs, between the electricity consumed, and wear and tear on the equipment. However, going back to when 57th Street was the Q's Northern terminal I ask: With the minimal amount of extra train movement that would have been involved, why did they not run each empty train out of the station and relay back on the downdown track so that downtown passenger could necessarily go there instead of having to scramble to find which track the next downtown train would be leaving from?
Changing ends is more operationally efficient than relaying the train...relaying the train takes time and effort to kick everyone off the train since passengers can't ride the relay.
Or as my tower operator source (who is qualified there) put it: "If you change ends you can get the train in and out in 2 minutes."
