The dining steward said hello to Frimbo and showed us to a table with a green cloth and a vase of fresh red carnations. "Haven't seen you since Monday," our waiter said to Frimbo. "How are you?"

"Fine," said Frimbo. "I'm celebrating my two-millionth mile."

"The three-millionth ought to be coming up before long," said the waiter. -- from All Aboard with E. M. Frimbo, by Rogers E. M. Whitaker and Anthony Hiss Some rail fans hang by the tracks with tripods and cameras. Others savor well-aged timetables or get misty at the mention of steam.

Then there are the mileage freaks -- which, in moments of self-revelation, is how they refer to themselves.

A strange yet wonderful breed, they take trains not to get anywhere in particular, but for the sake of "collecting mileage": that is, riding where few have gone before and even fewer will go after, then blazoning the achievement with maps and markers. The less traveled the track, the more "exotic" the mileage, the happier they are. And it hardly matters if there's nothing but a stock tank and week patch at journey's end.

"Maybe two dozen of us in the whole country are really serious about this thing," says Henry Maltby, 37, an erstwhile computer whiz from Bethesda, who guesses he's seen nearly half the track in the Lower Forty-Eight, plus thousands of miles more in Canada and Alaska. "It's not something you can explain. It's just something you have to feel."

His right leg working under a lunch table like the Broadway Limited at full throttle, Maltby hovers over a Rand-McNally Railroad Atlas at a grade school in Laurel, where the Railroad Enthusiasts of America, Chesapeake Division, are having their monthly meeting. Leafing through the pages, he wields a red felt-tip pen on the places he's been, and stares glumly at the track he's yet to ride.

"South Dakota," he says bitterly at a pristine page. "Hardly anybody has trackage in South Dakota."

Turning to Vermont, he points out, extending from Bellows Falls to Ludlow on the defunct Rutland line, a red-inked finger straining toward Rutland, a quarter of an inch beyond, like Adam reaching for God in the Sistine Chapel's ceiling.

"This sort of thing, dangling mileage, is especially irritating," Maltby says. "I had only 11 miles to go when the track washed out and we had to turn back." He tugs at his beard. "Very disturbing."

The hardiest of rail fans ("don't say 'buff," warns Maltby, "because in general we dislike the word"), mileage freaks are also the rarest; they can also be the most dogmatic, in a hobby that sizzles with strong opinions anyway: "That guy," Maltby remarks of a chap who had missed a chance at new mileage in Canada after a recent weekend of riding the rails in Maine, "ought to be drummed out of the fraternity."

There's frenzy at work here, and a touch of desperation, as diehard mileage freaks scurry for more track in a constantly shrinking rail system. Amtrak -- a name that still comes lurchingly off the tongue -- is usually the only game in town where riding's concerned. So the freaks, who tryically will go to extraordinary lengths and brave untold hardships to experience an odd stretch of track of a few miles or so, must wait for special excursions or charters, or, in extreme cases, take matters into their own hands by hopping the freights with hobos.

The halcyon days of passenger railroading, when the likes of Lucius Beebe traversed the landscape in "private varnish" (what the cognoscenti call luxury business cars), are long gone and won't be back. In the Twenties and Thirties, Beebe's time, there were almost a quarter of a million miles of rail in the continental United States, and proud, venerable lines such as the Pennsy and Sante Fe. There were trains like the 20th Century and the Green Mountain Flyer, the stuff of legend and song. Nowadays, though, what with mergers leading to bankruptcies and a lot of track getting wrenched from Mother Earth, there remain fewer than 200,000 miles of rail -- most of it strictly freight. The Official Guide, the monthly compendium of all railroad schedules nationwide, has shrunk from three inches to less than an inch in thickness over the last 50 years.

What's more, the most successful mileage freak of them all, actually the greatest allround rail fan in history, left the scene just a month ago. At his death on May 11, at the age of 81, he had accounted for a total of 2,748,636.81 miles on railroads all over the world, and his final tally, still being figured by his travel agent, probably will surpass 3 million. His name was Rogers E. M. Whitaker, but he was better known, through his articles in The new yorker, as the peripatetic lexicographer in homberg and tweeds, Mr. E. M. (Ernest Malcolm) Frimbo.

Now the burning question in rail fandom is who if anyone will be Frimbo's successor. He or she (a few, though not many, women are rail fans) will have to combine curmudgeonly charisma and a literate sensibility with an unbridled passion for trains. The young man ventured another question. "Mr. Frimbo, I am faced with a tough decision," he said. "I am more of a passenger-coach fan than anything else, and I, with some other fellows, have the opportunity to buy one. On the other hand, I could spend that money riding around the country on trains. Would you give me your advice?"

"It's a tough choice, all right," Frimbo said. "But the answer is plain. Ride. Do the U.S. Cover as much ground as you can. In five years, you won't be able to go from coast to coast by train. I have traveled one million nine hundred and fourteen thousand seven hundred and eight miles, by my latest reckoning, and I have never regretted a single mile."

"Mr. Frimbo, I will take your advice," the young man said firmly. "I admire you. You are like an encyclopedia. I would just love to copy some of your life, if at all possible. I have traveled ten thousand two hundred and ninety-two miles this year."

He paused, and Frimbo said, "Good." -- from All Aboard with E. M. Frimbo by Rogers E. M. Whitaker and Anthony Hiss Henry Maltby grew up in Arlington, next to the Washington & Old Dominion line, which ran from Alexandria to the foot of the Blue Ridge Mountains, but later became part of Route 66. His first train ride, from Union Station to Baltimore, was a gift from his parents on the occasion of his fifth birthday. His first piece of exotic mileage, that same year, was a run from Cherrydale to Leesburg. When he was in high school at Sidewell Friends, an uncle took him on a steam excursion into the wilds of Virginia, and Maltby was hooked.

By the mid-'60s, he yearned to see the country, and decided that a train was the only way to go. "After a while," he says, "I was riding the different routes not to see the country anymore, but just to ride the different routes as an end in itself."

With rumors of railroads about to go under and lines about to be disbanded -- "as Amtrak came in, it seemed as if the whole world was coming apart" -- Maltby feverishly hopped onto as many trains as he could. Between 1966 and 1971, before many final whistles blew, he made a dozen round-trips to the West Coast, and mastered the fine print of train schedules so he could come by special fares.

But it was just a few years ago in Hartford, Connecticut, that he really extablished himself as a mileage freak to be reckoned with. At a national convention of the Railroad Enthusiasts of America, Maltby happened to be in the audience when a man behind the lectern announced an excursion from Newark, New Jersey, to Buffalo, New York, over seldom-traveled track of the old Lehigh Valley and Erie Lackawanna Railroads.

With fellow freaks looking on in admiration, Maltby shot up from his seat, waved this arms, shouted "Where can I buy a ticket? Where can I buy a ticket?" and started throwing $20 bills into the air. "I think I made my point," he says today. Maltby's total mileage to date: about 250,000. His unduplicated track mileage: almost 100,000.

"It's easily explained why people get as much as they can," say David Morgan, editor of Trains, the hobby's preeminent magazine, and a mileage freak himself. "The railroad is totally connected, but has infinite variety. To say you're familiar with New England is not to say you're familiar with Southern California. They're facets of the same character, but the shadings and nuance are different. I suppose if you were involved with a painter, you would want to see everything he painted. Well, the railroad's like that. It's an all-absorbing work of art, and completely engrossing. The more you know, the more you want to know. Before long, the thirst is insatiable."

Reg Mitchell, a mechanical engineer who designs computer systems for NASA's Goddard Spaceflight Center, can date his first train ride to 1943 -- just before he was born. His mother, it develops, rode behind a steam locomotive from Alexandria to Fort Plain, New York: a total of 850 miles round trip.

A trip he remembers better, though, came in November 1978: "Basically a mileage trip up in Northern Ontario."

The train carrying Mitchell and his party left Toronto on a Friday evening, and ran 228 miles to North Bay, where everyone spent the night.The next day, they rode the Northlander on the Canadian Pacific to Sault Ste. Marie, where they bedded down once more.On Sunday morning, they set out from Sault Ste. Marie. Forty-two miles to the north, the locomotive pulling them hit a broken rail joint and jumped the track.

"The car I was in actually stayed on, but it bumped to a fairly rapid halt from 30 miles an hour," Mitchell says. "I guess it was kinda fun."

The group decided to wait by the wreck, in 20-degree weather, for the regular Sunday train service on the Algoma Central. The train duly appeared from the north and they all got on, riding back to Hearst, the Moose Capital of the World. Catching a few winks in Hearst, they took a pre-dawn bus eastward to Cochrane, where they snagged a passenger-freight train to Moosonee with a bunch of Cree Indians on the Ontario Northland line. By this time it was Monday afternoon, in the middle of an ice storm, so 15 minutes after the train pulled in, they flew by Otter prop plane from Moosonee to an ore-processing center in Timmins.

"We had these two guys who looked like typical Canadian bush pilots," Mitchell says. "We were flying 2,500 feet over snow-covered marshland into 50-mile-an-hour headwinds and ice, and one of two generators on the plane gave out. When the pilots worked the de-icers, you could hear the ice coming off the propellers and clattering against the fuselage. Not a pleasant noise."

From Timmins, it was another bus connection -- this time to the main line at Porquis Junction, where they caught an overnight sleeper back to Toronto, arriving early Tuesday morning. In Toronto, they rode around in the subway all day. Total mileage: 1,422.

"Explain it?" says Mitchell. "I don't try to explain it." Mileage freaks are a competitive but subtle lot, who couch their most mortal challenges in innocuous queries. Bruce Heard, an Amtrak public-relations officer who spent eight years as Rogers Whitaker's travel agent, once sent the great man a postcard asking, casually, whether he had ever ridden an arcane route from Duluth, Minnesota, to Superior, Wisconsin, as Heard had just done.

"My track charts of the Duluth region are in a packing case, so I cannot answer one question about a certain interchange," Whitaker began his reply. "My experience in the district is limited," he added, then went on to name every railroad in the area. It was downhill from there.

"As for the DW&P, I can only offer steam haulage in the triweekly CNR buffet-sleeper, munching the familiar lamb chops and peas and then downing a quarter of a raisin pie and black tea before bedtime en route to Winnipeg. But all this is old-hat to you, I am certain. . . Oh, we -- in our innocence -- thought we were Kings of the Road. You win!

"Note: Dr. Frimbo has upped his magic number of mileages to 2,412,967. He'll never make it." Mileage freaks like odd track better than run-of-the-mill stuff, but beyond that, they make other distinctions. Daytime is better than nighttime, though a full moon is acceptable, and scenic mileage beats our urban grime. Best of all, though, is moving in style, the height of which -- some folks say -- is the steam locomotive. Steam saw the last of its scheduled runs in the late '50s, but it will be back again for Southern Railway's Virginia excursions out of Alexandria Station starting this weekend.

"The steam locomotive is really a thing alive," says W. Graham Claytor Jr., Southern's former president who's also a rail fan. "It talks. It responds. It's like an exciting animal. Unfortunately, it's not a very efficient animal in today's world."

David Levine, a courier for a local delivery service, is a steam fan who talks in breathy bursts. Says Levine, who goes by the nickname "Superheater" because of his avocation, "It's a memorable experience to see something that was a rusty pile of junk just a few months before suddenly come to life. When they crank up an old engine, and open up the throttles, it's ritualistic."

There's something about the cinders and power and noise that makes you feel at one with the beast. At least E. M. Frimbo through so.

James Bistline, Southern's assistant to the president, remembers one steam run years ago from Augusta to Savannah, Georgia. Bistline showed up at the station early, when, to his surprise, he saw a tall, tweedy figure advancing out of the morning mist.

"Why, Rogers," Bistline gasped. "I thought you were in Poland!"

"I was," Rogers Whittaker replied. "But I flew all night to get here. You didn't think I'd miss this, did you?" GETTING ON TRACK Southern Railways, which got out of the passenger business a couple of years ago, is bringing it back this weekend and again two weekends later for all-day steam train excursions from Alexandria Station through the Virginia countryside. Excursions other weekends will be pulled by a diesel locomotive.

The first trip, to Front Royal and back, leaves on Saturday at 8 and features the scenic splendor of the Appalachian foothills as well as the mechanical splendor of steam. At Front Royal, there'll be a three-hour layover -- time enough to feast on a ham and chicken buffet and get the cinders out of your hair. (Steam travel, especially when the windows are open, can be a messy business, but that's half the fun.) If you want to go in real style, you can book yourself a first-class seat on the parlor car -- in this case a 1948-vintage round-end observation car known as the "James Whitcomb Riley," built originally for the New York Central and owned now by Washingtonian John Hickman.