With a splash instead of a screech, Redbird subway car No. 7835 made its last stop today.

It was born around 1959 in Berwich, Pa. It spent more than 40 years under and above the streets of New York, carrying far more than a million passengers within its ochre-painted steel walls. And at 1:08 p.m., it toppled over the edge of a rusty barge off the coast of Delaware, traveling 80 feet to its final resting place, where its new passengers, all nonpaying, will be blue mussels and black sea bass.

The cause of death, according to New York City Transit, was old age and the high cost of maintenance.

''Goodbye, Dr. Zizmor, forever,'' said David Ross, the transit official who had the slightly crazy idea last year that maybe the agency could junk its oldest subway cars more cheaply by dumping them in the ocean to serve as artificial reefs.

It was not the first scheme that had been proposed for scrapping 1,300 rusting, rattling cars, known as Redbirds, which are being retired over the next two years as a new generation of trains begins to run, on the numbered lines. Because the old cars contain a layer of asbestos within their walls for sound and heat insulation, tearing them apart for junk metal would have involved a costly process of asbestos removal.