Herb -
I hate to tell you but 476 is scheduled to be out of service by mid September for its annual and scheduled maintenance prior to the winter season. Most days in September will have 3 trains of which 473 will be in rotation. Generally DSNG wont promise any locomotive on a given day but I will say there are 6 engines plus #18 available for service today and they are rotated based on train length, maintenance needs and service days. With a year round schedule it's a short window with every in service.