As evening begins, the tin-roofed shacks built only a few feet from the rail line are still too hot to sit in, so people gather to talk on the tracks instead. If they have money, men drink shots of cheap rice wine as their wives and daughters return with food for the evening meal.

Approaching trains are announced by bells and flashing lights at a nearby road crossing and playful children are shooed away as the men shift a step or two to the side. Conversation continues unbroken as the cars roar past.

It is day's end at one of Bangkok's communities of migrant workers. By 7:30 the next morning, most of its men, women and children older than age 14 will leave for jobs at the six-lane elevated highway being built parallel to the tracks, just opposite their shacks. Men employed in skilled jobs might earn $4 a day; women generally fill unskilled positions and are paid half that.

Most of these people, like Tawee Charoenpon, 39, still consider themselves natives of upcountry villages. They come to Bangkok, Thailand's only real city, to find temporary work after the countryside's rice crop is harvested in December and January. Often they stay permanently.

"In the old days we would take in the harvest, then lay down and take it easy for awhile," recalls Tawee, a stubbly-faced man with bulging eyes who looks as if Bangkok works him too hard. The months before the new planting in early summer were spent enoying festivals, lazy afternoons and, when they felt ambitious, repairing fields and farming tools.

But today, Thailand's villages are becoming overcrowded as the last arable land is brought into cultivation. With productivity growth lagging behind the growth in population, many people have been forced to seek their fortunes in the city. A severe drought this year has further heightened the exodus from the farms.

In addition, a sort of consumer consc iousness is spreading in many rural communities. People are less content with country fare when television, newspapers and returning neighbors tell them of the wealth of Bangkok. The only way to get in on these things, it is reasoned, is to go there.

It is estimated that 250,000 people will move to Bangkok to stay this year, pushing the city's population close to 6 million. Speaking rustic dialects that make city people snicker and with little understanding that few can prosper without connections in the city, most of the migrants end up with menial jobs like the ones on the elevated highway.

This year's growing number of migrant arrivals has led local newspapers to label them "the drought refugees." Editorialists have suggested these people deserve the same food and medical care being given to Cambodian refugees, but so far there is little help.

This winter Tawee harvested the six acres of rice land he farms in Nakhon Sawan Province, about 150 miles north of Bangkok. Six weeks ago, after his funds ran down to about $30, he decided to move his wife and two daughters to Bangkok, where he had worked off and on for the past five years.

Having helped build shops and an amusement park. Tawee had learned how to handle carpenters' tools. Thus he got a carpenter's job at the elevated expressway, an $80 million project designed to relieve Bangkok's choke streets when it opens a year from now. his wife was hired as a laborer.

The jobs are better than many they might have got. There is free housing in the tin and plywood shacks provided by the consortium of Thai companies building the highway. The companies have run electric outlets to the huts and the large metal tanks that are spaced out along the tracks are kept filled with water.

Perhaps more important, relatives and long-time friends -- without whom country people are rarely happy -- are everywhere. Tawee's home village has established a sort of colony at the highway project. Eight families, many of them sharing Tawee's surname of Charoenpon, occupy adjoining quarters.

This presence of relatives can help cushion the shock of city life, since it provides someone to borrow money from, look after the children, or stand up with you in troubled times.

Still, the shacks are not the same as the homes left behind. In place of the spacious wooden rooms common in villages in Nakhon Sawan, these migrants live in cramped and dank cubicles, some of them too small to stand up in. The shacks are built on stilts over a canal that breeds swarms of mosquitos.

At night there is the din of piles being driven to firm up the ground (most of Bangkok is only a few feet above sea level) and trains passing by the family's front door. Couples worry constantly for their children's safety.

"A man was killed on the tracks four or five days ago," says Tawee. "He had finished work at 11 p.m. and fell asleep on the tracks."

In addition to dangers like these, the project offers no job security. Tawee and most of the other 700 people assigned to his two-mile section of the five-mile expressway are hired by the day and may wake up to find themselves unemployed. But Tawee reasons that having no contracts can work to his advantage as well.

"Who knows if I may get tired of the job and decide to go home?" he asks.

Foreigners often conclude that Thai peasants are averse to labor. Tawee and his friends would not disagree. Their conversation is loaded with jokes and anecdotes whose moral is that drinking, carrying on with women, and staying home and doing nothing are what makes living worthwhile.

But these migrants also recognize they must work hard, lest they starve. To Tawee a major failing of city life is the lack of freedom to decide when to work and how much.

"Wage earners can never feel at ease," he explains. "It's because they have to follow someone else's orders. At home if we decide to knock off for awhile, that's up to us. No one will say anything."

Company rules require Tawee to show up at 7:30 a.m. His job is to build wooden molds that are filled with liquid concrete, then broken away when it has set. As a laborer, his wife moves building material, digs trenches and carries land-fill. The crew gets an hour for lunch, with the shift ending at 5 p.m.

For those up to it, there is often a four-hour night shift, which pays double time.Under the illumination of floodlights, roadgraders, tractors and teams of laborers continue the job and the area falls silent only after 11 p.m. Tawee scoffs at night work, however. He does not have the energy after putting in a full day.

He and his wife make about $6 a day. From this they feed their two daughters, put some aside for school fees, and send some to the home village (as everyone going to the city is expected to do).

The family plans for the daughters to return to Nakhon Sawan where the eldest girl, a 10-year-old, will resume school. Tawee and his wife will stay behind until next fall, when tending and harvesting the main wet season rice crop will require their return as well. In the meantime, they make the best of city life they can.