Before the tunnel, there was Baltimore.

Not the sparkling, spanking new city of the Inner Harbor and Harborplace, of the Charles Center, urban homesteading and ethnic festivals -- a national model for urban living -- but grimy, old, row house Baltimore. It was a negative image implanted in the minds of generations of interstate travelers.

They threaded their way through the city bound south for Washington or north to Philadelphia or New York, and Baltimore became known as "the bottleneck."

And then came the tunnel, first authorized by Congress in 1938 and finally opened Now. 29, 1957. "With the opening of the new tunnel-expressway system, this bottleneck is forever broken," said the promotion literature, which further promised the 18-mile system would "whisk north-south traffic through the metropolitan area at open country speed."

But almost as soon as it opened, the 1.7 mile tunnel itself became the bottleneck. And now, while the city it was designed to avoid has undergone a glittering renaissance, the tube under the Patapsco has become the thing about Baltimore that makes people sweat, steam and swear.

With the holiday season at hand, signs over the toll plaza wish travelers a Merry Christmas and Happy New Year, and many will need all the good cheer they can muster to get through the tunnel in good spirits. On such occasions, traffic inevitably backs up for miles, despite posted warnings of impending tie-ups. As they sit, stalled and fuming, more than a few motorists have compared the tunnel, with its five million gritty white tiles and sometimes pungent odor, to the world's longest urinal.

To be cursed and maligned and avoided at all costs -- including $495 million for a new tunnel now being built -- seems a sad fate for the tube touted as "one of the modern wonders of the world" by Baltimore Mayor Thomas D'Alesandro during the 1957 dedication ceremonies.

Within a year, there were calls for a second tunnel, eventually rising above the mouth of the harbor as the Francis Scott Key Bridge. And today, work proceeds on the brand new Fort McHenry tube to take the motorist under, over and through the city once again on Interstate 95.

The once wondrous Patapsco River Tunnel, as the original tube is officially referred to in annual bond reports, cost $130 million to build. "I'm building you a tunnel to last one thousand years," said the Norwegian-born engineer-in-charge, who had, well, tunnel vision.

The four-lane tunnel's first patron was a man remembered only as Mr. First, whose hobby took him to the front of every line leading to a new traffic facility. His earlier conquest was a new bridge in South America. Early on, a junk man with a horse and cart was denied entrance to the tunnel because his rig couldn't maintain the minimum speed.

The minimum speed has doubled since then, from 20 to 40 miles an hour, but the tunnel toll (which is also used to maintain the approaches) hass changed little over the years, from 40 cents for interstate travelers and 25 cents for commuters, to 75 and 35 cents, respectively, enough to bring in about $18 million a year.

The tunnel may be a bargain, but there are some drivers you couldn't pay to drive through it. For the worst cases of tunnel phobia, the authorities will supply a driver or, on occasion, a police escort.

Among those who dread the tunnel is Mary Jedrowicz, wife of tunnel chief Bernie Jedrowicz.

"Most of the time I only drive through there if I really have to," she said. "If possible, I'll take the long way around, just go through the city to get away from the tunnel. I don't know. I guess I just get claustrophobia. It seems like the walls are closing in on you."

A related tunnel terror stems from the notion that the tube leaks, even though it is buried under 25 feet of muck. The tunnel does not leak, but this fear is fed by icicles that form from condensation of hot exhaust gases in the air dect above the traffic portion of the tube.

Actually, there is more to the tunnel than meets the eye. Its catacombs contain thousands of boxes of civil defense stores, aged crackers and old water, and darkened rooms that are supposed to serve as shelters along withh the tube itself for more than 10,000 persons during a nuclear attack.

The tunnel is daily drama. Flourescent tubes are broken: there was a particularly bad rash during the summer of 1979, the suspected culprit a trucker with a sling shot. Gates are crashed, and crashers who are caught -- about 10 a month -- are charged $9.75 each. On the northern approach to the tube, an airplane has landed, and a herd of cattle roamed free.

The tunnel's busiest day was July 3, 1976, during the three-day Bicentennial weekend, when 89,856 vehicles went through, about 25,000 more than normal. The lightest day was Feb. 19, 1979, during a blizzard, when 10,469 hardy drivers made the trip.

The first fatality, blamed on speeding, came on Sept. 18, 1975. The last of six fatal accidents happened March 25, when tunnel maintenance worker William Amos was hit by a tractor trailer.

The tunnel's first fire was intentional, part of a drill during the early days when traffic was light enough to close one tube. During the drill, they discovered the hoses and the water valves didn't fit. The fire, fortunately, burned itself out.

The most dramatic fire came in 1976 when an oil truck hit from behind burst into flames at the northern end of the tube. With 200 cars trapped behind it, tunnel workers built an earthen bulkhead and desperately diverted the leaking oil off the road an into the harbor, to the vocal displeasure of state environmental officials on the scene.

The environment is, however, on the minds of tunnel authorities. There is even a greenhouse, hidden behind the maintenance building below the roadbed, to supply the Mexican roses (the only plant that seems to survive the fumes in truck lanes 1,2,3,12,13, and 14), pansies and marigolds for the islands between toll booths.

Back in the 1960s, a German gardener reigned supreme over the greenhouse and landscaping. With 30 state prisoners working for him, the German was a force to reckon with.

"I'd put up a sign, Christ, he'd come along and put up a tree in front of it," said Henry Hopkins, chief of maintenance. "I said you gotta move the tree. He'd say no, it's easier to move the sign. Nine times out of ten I had to move the damn sign."

Use of prisoners, by the way, was discontinued after some allegedly got into the civil defense supplies and stole drugs from the medical kits. Also, Hopkins said, the prisoners complained that trash pick-up, one of their tasks, was too demeaning.

In one sense, some tunnel employes are prisoners of their jobs. They are the people who take your money. There is a secret passageway under the 14 toll booths connected to the tunnel office building. It is locked at all times, an empty corridor that sounds busy with the constant clanking of coins dropping into hugh metal vaults from the automatic change chutes above. Fourteen sets of stairs lead from the passageway to the booths, but tolltakers may descend into the corridor only when a sergeant inside the control room pushes a button.

For the 48 tolltakers, the hours are lousy, the pay abysmal and the work tedious. Tolltakers must make up the difference if they come up short. Tolltakers often take the rap for tie-ups onver which they have no control, and sometimes the bills they change are greased with spit. They work a different shift every week and rarely get their holidays when everyone else does.

When the tunnel opened, bridges and tunnels administrator Louis J. O'Donnell boasted, "Our toll collectors are all women. Women are best suited to the job; they're more accurate, more courteous, and the work doesn't seem to be so monotonous to them."

One of those first women tolltakers was Bea Hasenei, who is now in charge of the force. "When I started, more of our employes were more dedicated," she said. "We required a high school education then, now we'll accept eighth grade. In the 60s, they couldn't get enough with high school, so instead of raising salaries, they lowered the requirements."

The first male tolltaker was hired in March 1968. He left 11 months later, to an unknown future. Today, there are 12 men and 36 women in the tolltaker army.

Tunnel tolltakers are encouraged to aspire to the elite job of Toll Collector iii, the highest paying slot at $9,625 to $12,483 a year, available to those able to conduct at least 400 transactions an hour. "Rather than just a job," Toll Topics urges, "Toll Collectors should look upon their position as an opportunity for career growth."

"This is the worst place to be, outside of jail or the hospital," tolltaker Charles Wallace told a truck driver passing through his lane the other night. cHe wore ear plugs because, he said, some veterans of the tollbooths have experienced loss of hearing. In 1980 alone, half the tolltakers quit.

Turnover among the 102 tunnel police is also endemic; as many as a quarter of the entire force leaves each year. Starting pay is lower for a tunnel cop than for a state trooper or a Baltimore city officer. The pay ceiling is also lower, and it takes longer to get there.

"About 30 percent of our people come here intending to get training, then shove off for greener pastures," said Maj. Walter Wallace, a former postal clerk who is about to retire as chief of toll police.Toll police often attend Law Enforcement Day ceremonies held by schools to gain new recruits "but you're competing with the FBI, Secret Service, all those other agencies. Well, you can understand. . ."

The biggest problem in patrolling the tunnel is boredom. "It takes a certain type of person that can resign themselves," said Lt. Rowland E. Hierstetter, night shift commander. "If you have a proper frame of mind, you can overcome the discomforts and apply yourself in a manner where you'll survive."

To improve the survival odds, police do two hours in the tunnel, then two hours out.

"It's a job. I'm not unemployed. Somebody's gotta do it," said Mike Alban, at 23 a two-year tunnel veteran inside one of the glass-enclosed booths in the northbound tube. The booth helps to mute the whooshing sound of traffic, loud enough to constitute noise pollution by federal standards. The tunnel cops are required to wear earmuffs.

The nerve center of the tunnel looms about the south portal, a one-story building where police broadcast warnings of tunnel backups over CB Channel 3 (the trucker's handld for the tunnel transmitter is "hole in the wall") and interrupt your AM radio reception inside the tunnel with public service messages. (To bring you AM stations, the tunnel spent $50,000 installing its own receiver and transmitter more than two years ago. Tunnel engineers are now plotting ways to bring you FM as well.)

Prisoners are kept here, in a converted shower stall known as "our little slammer." A few feet away, seven softball and pistol trophies attest to the athletic and shooting skills of the tunnel corps.

It is here, also, that carbon monoxide levels inside the tunnel are closely monitored and 16 hugh fans located in ventilation buildings at both ends regulated. The fans suck the bad air from one duct over the tunnel roadway as fresh air is pumped in from a second duct underneath.

Such fancy maintenance, however, awaits completion of the new tunnel under Fort McHenry. The hope is that the new eight-lane tube -- to ranks as the world's widest -- will ease the flow through the old one. "Then," said Hopkins, "maybe we can get in and keep ours nice and pretty."