A second witness has come forward to corroborate claims that a subway train operator on the No. 4 line allowed an 8 or 9-year-old boy into the motorwoman's cab and maybe even let him drive the train a little. And the witness, Nessa Hampton, 53, says that not only was the boy in the cab with the female operator, but he was left to hang out there by himself while the unidentified woman exited the train at Union Square. According to her report, the motorwoman was gone for several minutes as she chatted with a colleague operating a No. 6 train across the platform. Hampton tells the Daily News, "He was right next to the controls. Suppose he touched something and the train started moving. There was no way this woman could have ran back to the train and stopped it." But not to worry—the motorwoman has explained to MTA officials it was physically impossible for the boy to operate the train because it requires 20-pounds of pressure. (Or a cinder block to override the dead man's switch!) Still, as Hampton told her daughter at the time, "somebody's going to get in a lot of trouble for this." Both the motorwoman and the conductor—who is believed to be the boy's relative—are currently suspended without pay.