How was the West really won? The railroads were responsible, of course.

Take all your straight-shooting, hard-fisted cowboys and toss them out the window. The mountain men made it first, the pioneers were second, but the railroads brought the people. The Union Pacific, Southern Pacific, Denver and Rio Grande Western-the names conjure up visions of train holdups, gunfights in one-horse whistle stops and packed, silver-town saloons.

In many respects, the land has not changed much in vast areas of the western United States. The long, steel ribbon still stretches across empty deserts and struggles up tortuous mountain passes. The mournful train whistles still harmonize with scattered coyotes.

At one time, all these rail spurs into places like Silverton, Colo., Cheyenne and Salt Lake City, all carried passengers. Now, only one train remains for the passenger-the Denver and Rio Grande Zephyr.

Running round trip from Denver to Salt Lake City, the Zephyr uses the same roadbed it rolled over 100 years ago. Privately operated, without any government subsidy, the Zephyr features the last non-Amtrak dining car in the United States. The train is operated with first-class flair through what is possibly the most spectacular country in America.

It used to be the California Zephyr, running from Denver to San Francisco, but the portion west of Salt Lake City was dropped nearly 10 years ago. The D&RG is seeking to drop the Salt Lake City to Grande Junction, Colo., portion of the trip, and the Interstate Commerce Commission is expected to rule on the request by early June.

For a train that has never been promoted by the railroad, the Zephyr has many friends. A cry of protest arose following the announcement of the proposed curtailment, and as a result the ICC held hearings. To those who ride the Zephyr, the cutback would be a painful loss; those who have never been aboard the train would lose a unique opportunity.

The Zephyr is the last embodiment of an era. The gambler, the prospector, the outlaw and the lawman all rode this train. And you can still do so, just as as I did.

The Zephyr looks like a long bullet in the predawn light, before a 7 a.m. Sunday departure. The platform in Salt Lake City is busier than usual. The publicity surrounding the possible cutback has brought 80 passengers for the ride to Denver.

The two conductors greeting and boarding passengers on the siding in Salt Lake reveal their feelings when asked about the proposed curtailment. "Well, between me and Charlie, we've got 73 years working this train. It'd be a damn shame." Retirement is the only alternative, they explain.

The traditional cry of "all aboard" precedes the on-time departure by one minute. As the train rolls out, adventurous is the best way to describe the mood among the passengers.

This day, 270 members of the Rocky Mountain Railroad Club will board in Glenwood Springs, Colo., so the Zephyr has its full nine-car hookup, in addition to a baggage car and two engines.. The full power of the twin diesels will come in handy many times on the 14-hour trip. The train climbs from Salt Lake City, through Provo, into the Wastach Range of the Rockies.

As the Zephyr growls up Spanish Fork Canyon toward Soldier Summit, the first of the high passes the train must conquer on the road to Denver, deer scatter from the trackside. Pine-covered foothills become red rock skyscratchers along a series of murderous 180-degree switchbacks.

On the down side of Soldier Summit is the Utah town of Helper. Here, extra engines are kept to help long, laden freights make it over the summit. Thus the town's name.

On the outskirts of Helper, Castle Gate, a massive sculpture of layered rock, guards the entrance to town and the desert beyond. In the shadow of this natural wonder thrives a coal mining operation that provides the base of southeastern Utah's economy.

The Zephyr stops in Helper to change crew and pick up and discharge an occasional passenger. The train rolls downhill to the sprawling desert from here, through Price, Utah, toward Green River.

The dining car on the Zephyr features meals cooked to order right on board. That in itself is not uncommon. What is out of the ordinary is everything else about dining on this train. White linen tableclothes, polished silver and first-class service go with every meal. The food is worth the trip. While the cost of meals is not included in the $39 Salt Lake-to-Denver fare, the prices are far below those in most stationary restaurants. Both quality and variety are excellent.

If you are in a hurry to get to Salt Lake from Denver, or vice-versa, the Zephyr is not for you: The plane trip takes only 55 minutes. What the train offers is an up-close look at the country Zane Grey spun tales about. Wildlife literally teem throughout Utah and Colorado, particularly between Grand Junction and Denver. It is easy to spot deer. In fact, it seems to be a chore for the animals to get off the tracks as the train approaches-elk hardly raise their heads as the train rolls by.

The Zephyr follows the Colorado River for well over 200 miles. The train meets the river for the first time in Westwater Canyon, on the Utah-colorado line. Here the river is beginning to widen, prepping for a wild run through Cataract Canyon in Canyonlands National Park downstream, through the Grand Canyon and eventually into the Gulf of California.

Westwater is the first true indication of the rock formations that will become the norm as the river winds southward. Reds and pinks abound in rugged and delicate sandstone. Aspen trees grow on the banks of the river and the surrounding land is used for nothing more than grazing scraggly cattle.

The train rolls into Grand Junction, stopping briefly for passengers, then continues on to Glenwood Springs. Glenwood is a story in itself. Natural hot springs have made the town a retreat where people can enjoy large outdoor pools of hot sulphur water from deep within the earth. There are also vapor caves, and the town has a steady tourist trade all year. There are two hotels at the resort and this is a destination stop for Denver and Salt Lake passengers.

Beyond Glenwood are several small towns, but the majority of the country lies empty and unspoiled, much of the terrain being inaccessible by road. This is where the supporters of the Zephyr find their strongest argument. Riding through this portion of Colorado by rail prevents any abuse of the delicate natural environment.

And, winding alongside the eversmaller Colorado River, one can't help but think about the people who forged this railroad through the Rocky Mountains. How many lives were lost providing this safe, comfortable trip?

The train crosses the Continental Divide in the Moffatt Tunnel, over 9,000 feet high.From here we roll through 29 more tunnels into Denver. From the foothills in Plainview, the night lights of Denver twinkle in the dark distance.

One can fantasize while riding the Zephyr, about imminent Indian attacks, holdup men around the bend, or becoming gold towns over the next hill.

The train runs six days a week, with 7:30 a.m. departures from Denver on Monday, Thursday and Saturday. It pulls out from Salt Lake at 7 a.m. each Tuesday, Friday and Sunday.

People from all over the world have ridden the Zephyr. This particular Sunday, couples from Australia, Hawaii and Falls Church are on board. A man from Chicago has come to ride for the second time: In 1941 he had shipped out on the Zephyr en route to the European battlefields of World War II.

Service from Salt Lake will continue at least through June 1, even if the railroad is granted its cutback request. The last time the line applied, the ICC turned them down.

Richard Cloud, the Zephyr's fireman, perhaps summed it up best: "When you ride this old girl, it's like stepping back into the 19th century."

He was right. CAPTION: Picture, no caption, Photo by John Harrington