From Andrew McLeod of Arlington came this brief letter:

"An old saying erroneously implies that it is easy to take candy from a baby. It is not.

"It is even harder to take a balloon from a 4-year-old. Please ask your contacts at Metro why they used balloons to promote the opening of the Orange Line and then refused to permit children to carry the balloons home with them on the train."

All my adult life I had heard the "candy" expression but had never questioned it. People would say, "It'll be easy -- like taking candy from a baby." And I'd nod like a dummy and let the statement go unchallenged. If I had any smarts, I would have realized that you can't take anything from a baby without triggering a protest.

I took Andy McLeod's question to Cody Pfanstiehl, who is Metro's manager for all the problems that nobody else wants to manage. As usual, Cody found a way to put a good light on everything Metro does -- even taking balloons away from babies.

"For starters," Cody said, "Metro didn't supply the balloons. They were supplied by a citizens' association.

"Second, there is no rule that says balloons can't be taken aboard trains."

"However?" I anticipated.

"However," he went on, "it is our responsibility to discourage anything that might distract people from giving their full attention to the arrival of a train at 50 miles an hour. Can you picture the danger that would be inherent in a balloon getting loose near the edge of a crowded platform as a train came whizzing in? My guess is that Metro attendants suggested, politely, that the balloons were potential hazards. If anybody actually ordered a parent to take a balloon away from his child, which I doubt, he would have exceeded his authority."

"While you're wearing your Manager of Explanations hat," I said, "let me bounce another question off you. I have a postcard from Milton Franz Spitz of Arlington that is also about your new Orange Line. Milton asks, "When are they going to erect shelters over the indoor/outdoor escalators along Wilson Boulevard?"

"That one is easy," Cody said. "If the county wants shelters and comes up with the money, there will be shelters. However . . ."

"I win!" I exclaimed. "I bet myself 10 billion trillion dollars there would also be a 'however' in that explanation."

"No, really," Cody said, "this is a very legitimate 'however.' Transit system safety engineers have learned that when an escalator brings people to a covered landing area, they will not venture out into bad weather until they have taken a few moments to adjust their clothing -- to button up, put on rain hoods, wrap themselves in scarves, and all the rest. If the landing area is limited in size and it quickly fills up with people, those ascending on escalators can find themselves in danger. So mass transit engineers have learned that unless a large landing area can be provided, it's better to let people on the escalators see what's going on in an uncovered landing area, so that they can begin adjusting their clothing as they near the top."

Does the machinery itself need to be protected from snow and rain? If the top of the escalator is exposed to the elements, will the escalator malfunction in bad weather? The answer to both questions is, "No."

As Cody put it, "Many cities that have worse winters than Washington -- for example, Stockholm and Hamburg -- have unprotected escalators that are exposed to severe weather conditions. They work fine."

P.S.: If you're about to write to tell me that one escalator in a station you use frequently is "out of order more often than not," consider this: In many stations, Metro uses an "unbalanced" system during certain hours -- one up, one down, one turned off so that people can walk it in the direction of the peak flow of traffic.

Before you assume that any Metro escalator is out of whack, ask an attendant. That escalator may have been turned off on purpose.

Or it may really be out of order. Machines do have their off days, of course. They're only human, you know. OLD-AGE INSURANCE

When Rick Lerner was 14 and the editor of "The neighborhood News" in Chevy Chase, I began speaking politely to him. I speak politely to all young people in the news field. I have lived long enough to see several copy boys become managing editors.

The latest news on Rick is that, as a junior at Tulane, he has won the Pacemaker Award given to the nation's finest college weekly newspaper. Rick is editor of The Hullabaloo, Tulane's 80-year-old campus newspaper.

I'm glad we have Social Security, but being on the right side of the young phenoms is even more practical.