(a) The purpose of this part is to promote the safety of railroad operations and the health and safety of railroad employees, especially those who are directly involved in a critical incident by requiring that the employing railroad offers and provides appropriate support services, including appropriate relief, to the directly-involved employees following that critical incident.(b) Nothing in this part constrains a railroad from implementing a critical incident stress plan that contains additional provisions beyond those specified in this part (including provisions covering additional incidents or persons), provided that such additional provisions are not inconsistent with this part.