For the last part of its outbound trip, the Orange Line is in the middle of Interstate 66. (Karen Bleier/AFP-Getty Images)

Transit riders frequently tell me they are baffled by the train operators’ announcements about “service adjustments.” But then, the more they understand it, the angrier they get.

It’s usually not good for the riders aboard the train, which is either going to stop and wait for several minutes, or skip a station.

Nobody likes to wait. And having the train hold means that the directors in the operations control center want to put more spacing between several trains that have bunched up, just the way buses do on crowded routes.

If you’re waiting on the platform, it should make a lot of sense to un-bunch the trains. That means you won’t see an enormously crowded train, followed very soon by a relatively empty one. If you are aboard the waiting train, the “service adjustment” is likely to increase the number of people boarding at the upcoming stations.

The other side of a service adjustment is that a train might be ordered to skip a stop — perhaps, your stop — in order the shorten the gap with the next train ahead. The operator should announce this adjustment in time for riders at the stop to be skipped to get off at the previous station and wait just a short time for the next train.

During my weekly online discussion Monday, an Orange Line rider asked a more specific question about schedule adjustments that I couldn’t respond to during chat time. Here’s the question:

“I get off at West Falls Church. Frequently in the evenings there are 2-6 minute “schedule adjustments” occurring between Ballston and West Falls Church (sometimes they just sit at West Falls Church without allowing passengers to exit). Since we’re already at the end of the line, would it be possible for these schedule adjustments to occur at Vienna? They cause a lot of [people on] the train to miss their buses/shuttles.”

I sympathize with these riders not only because of the missed connections, but also because that western section of the Orange Line already feels like the longest ride. The homeward-bound trains out of D.C. are packed in the afternoons, and once the trains emerge from the tunnel, the ride seems to get warmer on a sunny day in summer.

But this is a different scenario from the other service adjustments I’ve described. Holds at West Falls Church are most likely to occur late in the evening rush, and are related specifically to train congestion at Vienna, the Orange Line terminal.

When there are trains on either side of the platform, a westbound train has no place to go until one of the trains already at the platform starts the eastbound trip. A waiting train is most likely to be held at West Falls Church or Dunn Loring rather than on the tracks approaching Vienna.

(The online discussion format doesn’t allow me to trade messages with commenters, so I’m not sure what the rider meant by, “… without allowing passengers to exit.” I thought it unlikely the rider meant the trains stopped at the West Falls Church platform and did not open their doors to allow passengers to exit. Once in 25 years of riding Metro, I was on a train where my car doors didn’t open at a platform, and I don’t recall other riders complaining about that scenario.)