What a sanitized rail-riding experience one gets shuttling back and forth between Washington and New York on the Amtrak Metroliner.

Everything on the Metroliner is just the way it should be. Smoking is prohibited at all times. Need to be productive? Outlets to plug in your laptop are provided next to your seat. You can set your watch by the departures and arrivals. The clientele is such that if you're stuck with someone sitting next to you, chances are you'll strike up an interesting conversation and perhaps learn a thing or two.No doubt the high-speed Acela, scheduled to replace the Metroliner next spring, will offer much the same experience, in 20 minutes less time.

But there is another, very different, side to riding the rails with Amtrak, as I learned last weekend - not better or worse necessarily - just train travel of a very different sort.

My situation was that I needed to get to Pittsburgh on short notice to pick up a car and drive it back to New York. The price of a one-way airline ticket on a day's notice was outrageous, as expected, and Priceline.com was no help. The thought of the bus was unbearable, and I gave up hitchhiking years ago. That left the train.

From the beginning things weren't what I was used to. When the Metroliner's track number is called at Penn Station, a mass of humanity migrates to the escalator. When the ''Three Rivers'' train to Chicago came up (the only one departing that day) the masses stood still. This wasn't the train they were waiting for.

A trickle of folks made their way down to the track. One group made the mistake of boarding this train when they meant to get on one bound for Washington. A few minutes after the conductor delivered the bad news, somewhere south of Newark, their Washington train sped by.

The scheduled time from New York to Pittsburgh was 10 hours - from 12:45 p.m. to 10:45 p.m. In Philadelphia, we were told to feel free to wander around the station for half an hour while equipment was changed.

When we finally got going, an earnest conductor offered a short safety briefing, reminding us to always keep one hand free when walking down the isles. He informed us there was a downed tree up the track a way, which might delay us.

The ''Three Rivers'' train of the Amtrak Intercity service slid along the Philadelphia Main Line and then onto working Norfolk Southern track for the westward passage through Pennsylvania.

Metroliner passengers, whizzing along on Amtrak-owned track at 125 miles per hour, don't get the experience of sharing railroad tracks with freight trains.

You're a guest on these tracks, and you wonder how welcome you are. Amtrak does its best to stay out of trouble and keep its trains moving on schedule through a jam-packed corridor that it doesn't control.

Long freights came up fast in the opposite direction. Suddenly you'd see their headlight, hear their whistle, and feel your train shake and the air pressure momentarily change as they sped by.

Compared to the ride on the serene Metroliner, this was like being out at sea, exposed to elements beyond your control.

You felt as if this Amtrak train - coach cars, a bar car, a sleeper and several freight cars pulled by a double locomotive - didn't belong here. Outside one station we idled helplessly for 15 minutes waiting for a freight train to get out of the way.

Most of the passengers aboard were oblivious to all this. They seemed resigned to the routine. As nightfall came, they settled in, most fighting a losing battle to make themselves comfortable on double seats with fold-out leg rests. One gave up and rented an available sleeper cabin.

I always knew a station was coming up because the conductors - a rotund bunch - roused themselves from the seats they had monopolized in the bar car and ambled through my car to oversee boarding.

One of them wasn't aware Amtrak had started a freight service, arguing that would be illegal. Another warned there would soon be only eight empty seats on the train, though the expected rush of passengers never materialized.

Smoking in the bar car was permitted for a half hour in the evening, and it seemed like half the train took advantage. At dinner time, I dared to eat a microwaved meatloaf sandwich. Not bad! I went back for seconds.

As the train made its way westward, it slipped behind schedule. A Mennonite family boarded in Johnstown, Pa., as did a 95-year-old nun.

The conductors said I was lucky to be on a train running only an hour late; since Norfolk Southern took over the line from Conrail four months ago, delays have become routine, they said. Amtrak spokesmen verified this. One train pulled into Chicago nearly 24 hours late, one conductor said.

After what seemed like a truly endless journey, we arrived in Pittsburgh, intact. It was 11:45 p.m. I was a lucky man.