One Boston hospital administrator called it a crisis: Surgeries canceled because there weren't enough beds, taxis hired to ferry patients who had no other way home. At another hospital, stockpiles of linens were running so perilously low that staff began rationing them. Meanwhile, still other hospitals were forced to rely on the generosity of Boston police officers to deliver essential staff members to work. With snow piled up to historic levels, and the region's subways and commuter rail systems halted Tuesday, administrators labored to keep their hospital doors open, hobbled by a stranded workforce and patients unable to get home.