A portion of the North Bay’s Highway 37 will be closed for 32 hours starting early Saturday. The route will close just east of Highway 121, so Sonoma-Marin Area Rail Transit crews can fix a railroad crossing. The crossing is battered by decades of wear and tear from getting drove over thousands of times a day. The plan is for the highway to close at three a.m. on Saturday and reopen at eleven a.m. on Sunday.