The subway train announced its arrival with a screech of grating steel. The man was shoved from the car onto the platform by the eight p.m. crowd. The noise and the abrupt handling of his body brought him to awareness. Not that he had been asleep or unconscious. Although he might have been. He didn't know for sure. He found it hard to concentrate, but soon a sign over the platform came into focus: WESTBORO It meant nothing to him. The second thing he became aware of did. Another train had replac