Night train to Datong

Yodeling. The genuine Chinese version of the American version of Swiss yodeling from "The Sound of Music" emerged reedily out of the speaker under our sleeping compartment table.

The European melody contrasted strangely with the throaty hum of Mandarin seeping in from the passage outside. Even less did the Alpine gargling fit with the dun-colored Shan-xi plain scrolling rhythmically past the window of our warm and cozy compartment.

In the distance rose the abrupt fortress of brown mountains atop which the Great Wall twisted like the tail of some immense Ming dragon. Mud houses clustering in walled villages all along the base of the foothills. Maize farmers and some sheepherders.

Beyond the escarpment and the Great Wall lay the steppes of Mongolia -- a vast dry sea over which invading hordes had sailed into both China and Russia for millenniums, leaving a tribal fear that is reflected once more in the troop concentrations on the long Sino-Soviet border.

The yodeling rose to a falsetto crescendo. Then suddenly a brisk female Chinese voice took over the airwaves aboard the Datong train. I recognized the timbre and machine-gun-fire delivery even though the words were incomprehensible.

It was Peking Radio's Barbara Walters reporting the latest confessions from the trial of the "gang of four." The Monitor's Shan-xi-born, British-schooled assistant, Yang Zhikuan, interpreted the play-by-play commentary.

Up and down the wood-paneled sleeping car all other activity stopped as Chinese travelers gathered round each compartment's speaker and listened to the gripping daily serial. It fascinated them every bit as much as the Watergate hearings and trials had fascinated Americans in the '70s. As they listened, the solid old steam locomotive chuffed on at a steady 45 m.p.h. across the dry plain.

The sudden switch from Swiss yodeling to the gang of four was only one of several ironic twists that punctuated this journey from Peking to one of the more fascinating ancient crossroads of Eurasian history.

Another contrast hit as we drove up to the hotel in Datong, having emerged from the train in drizzling darkness at 5:16 a.m. The headlights picked out a massive, square-lined concrete building.

It had been designed and started by the Russians in the 1950s to house their advisers on coal mining. It now catered to Western capitalist tourists coming to see the serene but monumental architecture of three 11th-century Buddhist monastery buildings and the extraordinary 4th-century sculpture of the Yunkang Caves, remnants of China's Northern Wei Dynasty.

A few days earlier in Peking, I had come upon another such monument to Soviet retreat. An American trade fair, three years in the making, was being held in an exhibit hall built by Moscow. The structure was a mixture of Stalinist heaviness and sugar plum sets for a Tchaikovsky ballet. Amid the soft green and white pinnacles of the main showroom, booths showing United States hog-raising, computer technology, airliner design, and offshore oil-drilling rigs attracted some 20,000 Chinese visitors a day.

In the courtyard, a diminutive Chinese woman sat at the controls of a huge Payloader beside a beefy Midwestern American sales executive for International Harvester. She operated the hydraulic controls -- lifting the mighty bucket loader and dumping tons of imaginary rubble into a giant truck, then flexing the loader's midriff like a hippopotamus doing the Twist. Hundreds of Chinese gazed up in awe. When she finished her lesson at the controls, the American instructor asked her to pause on the running board while he snapped her photo. The Chinese audience beamed.

The show was a succes d'estime but sales were few. Nevertheless, the new era of friendship with the West seems far more widely popular -- and therefore stable -- than the vanished period of Russian friendship. The caution now setting in after the Nixon-visit honeymoon had run its course is probably useful in the long run. The chance of relations souring into a new period like the Opium War or Boxer Rebellion, in which Westerners pushed their technological superiority too far and provoked bitter reprisal, appears slim.

Moscow had made a mistake like that late 19th-century one. And now the monuments the Soviets left behind were playing host to Western "friends." (The words "friend" and "friendship" are still applied widely to Western tourists and businessmen.)

Yet another striking contrast hit as we drove along the 10 miles of bumpy road to the Yunkang Caves. The route was swarming with traffic. The road was black-topped -- but not with macadam. It was crusted with coal dust sifting from the bizarre stream of coal-carrying vehicles moving toward our car. There were big trucks, little trucks, and swaying carts piled high with random-size chunks of anthracite. On top of the latter there often rode several men, some sleeping on piles of gunnysacks. They were carting out fuel for strictly local use.

The ancient caves are carved out of hills on one side of a shallow valley. Directly across from them on the opposite row of hills are caves of another sort -- the mines that contain great beds of coal, some 200 years' worth of reserves at present production rates. This reserve, plus China's expected addition of offshore oil produced with American help, is one of the principal reasons for mild optimism that Peking's current "modernization" plan can overcome at least some of the many obstacles it faces.

Datong is also the site of a major locomotive factory. Its iron horses pull a continuous stream of coal trains down to the factories of Peking, Shanghai, and other industrial centers along the populous coastal strip of China. A modest amount is exported to energy-hungry Japan.

But back to the caves on the north side of the valley: If they are not among the traditional seven wonders of the world, they certainly belong among the top 20. They contain some 51,000 statues -- tier upon tier of Buddhas, elephants, "sky fliers" with halos, lotuses, acanthus leaves, disciples, flames, flowers, devils, beasts. The Buddhas range in size from a monumental 56-foot-tall placid figure to tiny two-inch likenesses. Except where erosion and vandals have taken their toll, the rich splash of color -- turquoise, terra cotta, sky blue, ocher, and lapis -- is remarkably preserved after 1,500 years of exposure to the elements.

The 53 caves were carved with only hammer and chisel in a span of just 34 years in the fourth and fifth centuries. Archaeologists guess that some 10,000 workers were employed on the job in the brief period before the Wei emperors moved their capital south to Luoyang.

But it is not massiveness that makes this cave sculpture so impressive. There are bigger Buddhas in Japan, dramatic cave sculptures in India. In none, though, is there such clear evidence of cultural mix between Europe, the Middle East, and north and south Asia. Here in these striking-colored Buddha legends are motifs from Alexander the Great's Greece (very European vine tendril designs , even a European face or two); Indian elephants and dark faces; Chinese pagoda structures; Persian flowers and scrolling; Wei designs from the steppes to the north. Some of the Buddhas themselves are modeled with Greek flow of drapery and body posture.

If we think cultural interchange is something the world has come to only in this "global village" era, these caves are a reminder that cross-pollination of cultures is as old as the Silk Road that brought these beautifully varied forms to this remote city, and sent China's inventions to the Western world. Marco Polo was not the only wanderer in those days.