Rail workers and transit officials agreed Tuesday to resume contract talks to end a two-day-old strike that has caused chaotic commutes throughout the San Francisco Bay Area and prompted businesses to claim the walkout is costing the region millions of dollars. The move came as political pressure mounted for a settlement. In a letter, the state controller, lieutenant governor and insurance commissioner urged both sides to return to the bargaining table. Gov. Jerry Brown did not sign the letter and has said little publicly about the strike. Members of the two largest unions representing Bay Area Rapid Transit workers went on strike early Monday after talks with management broke down.