CHILDREN WHO ARE veterans of the 747 may be puzzled by the raptured recollections of elders who, in the Time Before Television, once rode trains. But what aging traveler could forget childhood memories of monster locomotives, steaming and chuffing with power. And are the intimate secrets of strange back yards and dank mountain tunnels to be lost to jet-set generations?

Maryland train buffs hope not. They have happily joined forces with the administration of Maryland's train-loving Gov. William Donald Schaefer -- a man who has never turned down an offer of an engineer's cap -- to plan a series of relatively low-cost, half-day rail excursions around the state.

The weekend adventures, planned on a variety of vintage trains and timed to local fall festivals, are designed to draw tourists to small historic communities from Cumberland to Pocomoke City. They start Saturday, with a trip that originates at the Baltimore B&O Railroad Museum, and run through mid-October. Future trips originate in Maryland at Union Bridge, Federalsburg, Cumberland, Berlin, Bowie, Brunswick, Thurmont, Westminster and in Virginia at Parksley.

Saturday's 54-mile round trip leaves Baltimore for Sykesville, Md., with a two-hour stop at Ellicott City. Most of the train will be made up of diesel-drawn remodeled sleeper cars used during the week by Washington-Baltimore rail commuters.

The trip is to begin at a place and on an anniversary held sacred in train history -- "the very spot that the first American passenger train began 160 years ago," says John Hankey, chief curator of the Baltimore railroad museum.

The trip follows the ride of that train and the nation's first steam locomotive -- the Tom Thumb -- on their historic route west to the Romanesque Carrollton Viaduct, the oldest railroad bridge in the country, and then along the original Baltimore and Ohio path.

It passes backyard West Baltimore, whose dense, railway-spurred neighborhoods date from the 19th century, and goes past a 1767 Georgian plantation house. The rail route slices through Baltimore history, past the remnants of industries that fueled the city's growth, through an old rail yard and then along the twisting valley of the Patapsco River, once strung with water-powered mill towns, Hankey says.

Washington-bred children who think parents go to work to make policy can gaze out the train's broad windows and reflect on a time when parents went to work to make sailcloth or flour. Keep an eye peeled for reminders of the valley's history, including the few dams and millworker houses left in what is now a state park.

The train clings to the bank of the Patapsco, except for passes through old tunnels and crosses on bridges, on a route now normally used only by freight trains, past spots named for long-lost villages. The train turns back at Sykesville, a tiny, untouched 19th-century town tucked away in a hollow, and comes back to stop for two hours at Ellicott City, one determined mill town that refused to fade or float away.

This county seat of Howard County, with its steep Main Street and old granite buildings, is turning out to welcome Saturday's travelers, with balloons and sidewalk sales by the local vendors of antiques, crafts gifts and food. There's another B&O museum here, housed in the nation's oldest train station.

"This is another way to get people out and show them the texture of American life, out of their automobiles and on trains where they can get a different point of view," says Hankey, a former company historian for the Chessie System who apprenticed as a train engineer along the Baltimore to Brunswick line to expand his knowledge of railroading.

He never lost his love for the route, he says, and plans to go along Saturday. For a small state, Maryland packs in a diverse range of sights, Hankey says. "There's no better way to see that than from a train." TRAIN TIPS

Tickets may still be available for the trip to Sykesville, but you have to call the number below thisinformation. Excursions on following weekends show off the farmland of Carroll County, northeast of Baltimore and of the lower Eastern Shore; the mountains of Western Maryland; old stations of the Baltimore-Washington corridor; and the historic Potomac River Valley rail towns of Brunswick and Harpers Ferry.

Advance ticket prices for the trips vary. Adult prices range from $6 for a Bowie-to-Baltimore trip to $42 for the Baltimore-to-Brunswick trip. In general, round-trip tickets average about $8 for children ages 4 to 12 and $12 for adults. Children under 4 ride free. You can reserve tickets for any of the trips by calling 800/933-TRAK during the week.