There is a valuable coffee crop here, but it may never get to market.

The train from Luanda stopped coming to this provincial capital a year ago, after guerrillas opposing the Marxist government blew several wagons off the track just outside the town. Trucks and cars risk taking the road to Luanda, the capital, 125 miles to the west, only in convoys accompanied by Army escort.

Thus, for Paolo Jorge, the newly appointed commissar, or governor, of the province, the problem of how to move out the 16,800 tons of coffee that he estimates are stored away in the scores of small villages in North Cuanza is an all-consuming challenge.

Security is only one aspect.

"The villagers will not sell their coffee unless I can offer them something they want in return," Jorge said. "They want salt, dried fish, soap, sugar, cooking oil and clothes, and I have to get them."

The plight of North Cuanza, where all normal trade and commerce has ground virtually to a halt, is a microcosm of this nation's crippled economy. Since independence 11 years ago, Angola has slowly slipped back into a barter economy similar to early colonial times when Portuguese traders came into the interior offering salt, sugar and trinkets in exchange for local products.

The collapse resulted, in part, from the exodus in 1975 of more than 200,000 Portuguese, who were this country's importers, traders and exporters and who trained few Angolans to replace them. The decline was compounded by the new government's rigid socialist policies and then, increasingly, by the unending civil war that has torn up the country's road and rail network. $10 Eggs and Worthless Currency

For Jorge, who served eight years as Angola's foreign minister, the day-to-day realities of life and government outside the capital of this war-battered country have come as a shock.

The government has charged him with reviving economic life in this paralyzed province of 500,000 coffee- and banana-growing peasants living under the daily threat of attack from Jonas Savimbi's UNITA guerrillas.

During a reporter's brief visit to N'dalatando by helicopter in early July, Jorge talked for three hours about his challenge. He had broken away from an all-day meeting with provincial authorities called to draw up an emergency plan to bring in the coffee harvest.

He described his logistical nightmare:

First he must fight his own government bureaucracy for an allocation of scarce consumer goods to barter for coffee; second, he must buy or beg for trucks to bring his barter items here; third, he must send men out to widely dispersed villages to trade the goods for coffee. Finally, he must organize a convoy and Army escort to get the coffee to Luanda.

The state of North Cuanza speaks volumes about economic life in Angola today.

The national currency, the kwanza, is all but worthless. The value of goods calculated in the local currency is astronomical and, therefore, meaningless. For example, the current price of a single egg at the official dollar-to-kwanza exchange rate is $10.

In the capital's central market, a small pile of six to eight tomatoes, or as many oranges, are on sale these days for 1000 kwanza, the equivalent of $33. This is also the price of a single manioc root from which cassava, the main staple of the peasants, is ground.

Not only is the official exchange rate way out of whack, there is a mass of unspent and excess kwanzas but little to buy on the market. As a result, the value of eggs, tomatoes and oranges is measured not in kwanza but in bottles of beer and packets of cigarettes.

For instance, a single can of beer or two packets of cigarettes will buy one of those piles of tomatoes or oranges in the central market.

The economic mess is so extensive that government officials say they are not sure how to go about unscrambling it. Benvindo Pitra, a Planning Ministry official, said it was extremely difficult to get prices to reflect the real value of goods so long as they are in such short supply.

He blamed the mess on low factory productivity, the collapse of the internal trade network and "mistakes" made by the government during the first years of independence.

"The barter system we have now is a temporary thing," he insisted. "We are working to re-monetarize the economy. But it all goes back to demand and offer, even in a socialist system. "Oil Price Collapse Hits Hard

How to meet the demand for consumer goods, and sometimes even the basic food items sold cheaply in the state-run "people's stores," is a problem that this year is approaching crisis proportions due to the collapse of world oil prices, which determine the government's main source of income.

Oil exports account for about 90 percent of all government foreign earnings. Last year, Angola earned roughly $2 billion in oil exports. This year, it is counting on only about $900 million, a more than 50 percent cut.

Meanwhile, the country is becoming more and more dependent on imported food as the war steadily shrinks the land area planted in staple crops such as corn and manioc. Last year, government-controlled areas yielded only 300,000 tons of food, less than half of the national need. This year, production is down to about 240,000 tons, according to preliminary United Nations estimates.

Last year, the government had to spend $300 million on imports to feed the nation -- almost a sixth of its oil income. With the drop in that income and the increased need for imports, it appears likely it will have to spend one-third or more of its earnings just on food imports alone.

Another $300 million in hard currency is estimated by U.N. officials here to be spent annually on the large expatriate work force needed to keep the economy and government functioning, such as they are. This figure apparently includes the estimated 9,000 to 10,000 Cuban civilian advisers, as well as the 8,500 other cooperantes, or volunteers, working in Angola. War Is the First Priority

Government officials like Pitra insist the war will continue to get first priority even in these hard times.

Defense expenditures have been consuming somewhere between one-third (the official figure) and one-half (by western estimates) of the government's annual budget -- originally set at $3.4 billion this year. This burden has become particularly onerous because the government must use its hard currency to pay for Soviet arms and other imported war materiel.

To meet the financial crisis, the government in March adopted various austerity measures, including the suspension of private currency transfers, a cutback on official trips abroad and an end to hard currency allowances for traveling Angolans.

It is also scrambling to reschedule half of the $350 million to $360 million in service payments due this year on its relatively small $2.5 billion foreign debt, according to Mario Pizarro, vice governor of the National Bank.

He said Angola intended to pay back all short-term loans and credits, as well as payments due on its $200 million outstanding debt to the U.S. Export-Import Bank. But he said Angola would try to ease its load by rescheduling payments to East Bloc countries, whose loans account for 50 to 60 percent of the country's total debt.

One way the Angolan government is seeking to compensate for its foreign currency crisis is by mortgaging the 30,000 to 35,000 additional barrels of oil a day it expects to produce in 1987, Pizarro explained.

Government officials will also try to boost coffee and diamond exports, the country's two other main foreign exchange earners.

Repeated raids on the diamond mines of eastern Angola by Savimbi's guerrillas have nearly shut down the once lucrative industry. Production so far this year has been only 60,000 to 80,000 carats, compared to 1.4 million in 1980 and 2.4 million before independence, when the diamond trade here was a $200 million business, according to Chris R. Hellinger, a West German diamond trader.

Hellinger -- with the government's blessing -- is trying to reopen one of the largest diamond mines at Canfunfo, but he has refused to go forward with the project until Luanda provides him with 1,500 Army troops to protect it.

Coffee is the government's other great hope to compensate for the drop in oil revenues. World coffee prices remain high, and the government is trying to boost exports from 20,000 tons last year to 35,000 to 40,000 tons, according to External Trade Minister Gaspaar Martins.

This explains why Jorge's struggle to get soap, salt and dried fish into the interior of North Cuanza as barter items for the coffee crops there has become crucial to the central government.

And, government officials say, Savimbi's strategy to cripple Angola's key industries of oil, diamonds and coffee explains why his guerrillas have stepped up their attacks in the northern and eastern provinces since early this year.

Next: The massacre at Camabatela