Dear Dr. Gridlock:

I have been riding Metrorail since 1976, when the Red Line opened. In general I have been pleased, given that mechanical and personnel problems will always exist in this world of ours.

My pet peeve: that annoying voice at each stop telling us when the doors are opening and closing. The continual announcement is bad enough, but I think it is inaccurate. It says, “When boarding move to the center of the car.”

What about people who enter the front and rear doors? If everyone were to move to the center of the car, who would stand or sit in the front and rear sections? As I ride, I note that no one pays any attention to the announcement.

I would like Metro to do an experiment: Stop all these door announcements for two to three weeks. Let us then see whether people move about any differently within the rail cars. The respite from the annoying announcements might lend a measure of relaxation to us riders (customers).

Robert Linden, the District

DG: There was a method behind the voice that maddens many of my letter writers. Metro officials recognized that crowding of the rail cars was becoming a serious problem. There are only so many people who can jam into one of those things, although at cherry blossom time, we continue to test the limits of the sardine cans.

The transit staff, however, noticed that the passengers were rarely distributed evenly in a car. They tended to cluster around the front and rear doors. In the middle, there were gaps in the aisle, and even some empty seats.

Besides education — via the announcements — Metro also tried engineering. The newest cars have fewer floor-to-ceiling poles at the front and back. That was supposed to encourage people to move toward the middle, where they could get a grip on something besides a fellow passenger.

Did any of that work?

Next time you’re waiting for a Blue Line train, watch an Orange Line train go by. Or if you’re waiting for a Yellow Line train, watch as the Green Line train cars go by. Sometimes, you’ll see grim-faced riders distributed evenly. But I think that's because some of them got pushed into the middle by the overwhelming force of boarding passengers.

Many other times, you’ll still see tight clusters at the ends of the cars and gaps in the center. It doesn’t matter what the voice says or where the poles are.

These are my theories about passenger dynamics: People don’t like the confined space of the central aisle. Almost always, someone else is approaching from the front, back or side. But many riders don’t want to get caught in that spot in the first place, saying they fear getting trapped inside the car at their stop because the doors close too quickly at the crowded downtown stations.

I recently printed a letter from Dudley Schwartz of Rockville, a rider irked by the too-rapidly closing doors [Dr. Gridlock, March 18]. Schwartz urged Metro to concentrate on moving people rather than trains. Richard Layman, who writes an interesting blog called “Rebuilding Place in the Urban Space,” countered with a posting saying Metro could move both trains and people more efficiently.