Berlin subway pact has echoes of detente

East Germany is making strenuous efforts to minimize East-West German tension - despite Moscow's contrary efforts to emphasize East-West tension in the wake of new NATO missile deployments.

The latest evidence of ''damage limitation,'' as state and party chief Erich Honecker phrased it a month ago, includes:

* East Germany's turning over Monday of the surface rapid transit system in West Berlin to West Berlin administration. East Germany had controlled the system since World War II.

* The sharp increase in family visit approvals in 1983.

* Conciliatory remarks by an East German Politburo member at this month's congress of the West German Communist Party.

* Mr. Honecker's assurance this month that East-West Euromissile arms control negotiations would resume ''sooner or later.''

For four decades the West Berlin surface transit system, or S-Bahn, has been an anomaly left over from a chaotic occupation period. When a defeated Germany and Berlin were split - temporarily, everyone thought - into Soviet, American, British, and French zones, the surface transit system was awarded to the Soviet-zone administration, the subway system to Western administration.

In West Berlin the S-Bahn - which was a pioneer in urban transport at the end of the 19th century - quickly went into decline. The network of track radiates out from the hub of imperial Berlin, and since this hub is now in East Berlin, its routes no longer correspond to West Berliners' needs. The decay of the S-Bahn was further accelerated by West Berliners' boycott of the East German system during cold war years, and by East Germany's refusal to put needed investment into plant and upkeep.

The logical solution has always been for East Germany to sell or rent the S-Bahn to the West. But East Germany declined to do so on reasonable terms, and the Western occupying powers have feared changing the legal status of the system.

The agreement that turned the West Berlin S-Bahn over to West Berlin Monday is thus a landmark. It is read both as a sign of an economic need in East Berlin for the 80 million to 100 million marks ($29 million to $36 million) yearly rent , and as a signal of East-West German detente despite current East-West confrontation.

Equally important is the dramatic rise in the number of approvals granted to East Germans to visit relatives in West Germany - almost 60,000 in 1983, or 40 percent above 1982. These included permitting citizens of working age (who are otherwise barred from traveling to the West) to go to West Germany for relatives' funerals or anniversary celebrations.

At the West German Communist Party congress Jan. 6-7, East German Communist Party Politburo member Egon Krenz specifically expressed the hope that East-West German relations can be made ''calculable.''

In broader terms Honecker told the French weekly Revolution last week that he expected East-West arms control negotiations to resume ''sooner or later'' ''on a changed basis.'' This assurance would seem to run counter to Soviet insistence that Moscow will rejoin the strategic and Euromissile arms control talks only when NATO removes the 41 new Euromissiles deployed in Europe at the end of December.

The East German effort to calm tensions is especially noteworthy: Honecker is no gadfly like Romania's President Ceausescu, and East German Foreign Minister Oskar Fischer had just returned from talks in Moscow.