If you have reached this page then you have the disease bad and no amount of physco theraphy will help now, so read on.

THE OPERATIONAL PHILOSOPHY

Freight operations on the Easton & Potomac are based on two events; (1) the arrival of new cars on any of the four interchanges (N&W at Stanley, Southern at Broadway, RF&P at Brooke and C&O at White Hall) and (2) the generation of traffic from businesses located along the Easton & Potomac tracks. These two events set into motion all of the freight car moves that will take place on the layout. Because the layout only depends on these two events mistakes in car moves during a session are not an issue and are corrected during subsequent sessions. The only time the computer needs to know about the location of a car is when it arrives at one of the four interchanges from the Easton & Potomac. When a car is removed from the layout it will not be used in the next session. It must stay off the layout for at least one session before returning. This prevents cars that were placed on an interchange track to be picked up from showing up during the next session either on that same interchange or another interchange.
The process used to stage the Easton & Potomac generates random car arrivals and repetitive and random car movements. This prevents the same cars in the same trains session after session. It also means the locals (Broadway Turn and Hood Turn) will have regular switching moves as well as random switching moves. There are no staging yards used on the Easton & Potomac. Car Cards and waybills are used to direct the required car moves. However, switch lists could also be used. Waybills come from two sources; (1) interchange cars and (2) business located along the E&P tracks. The waybill identifies the receiver and car type required. For the interchanges these are preloaded into the "loaded" cars' Car Card. For the businesses the new waybills are placed in Business Cards until an empty (MT) car is available for loading at which time the waybill is removed from the Business Card and placed in the Car Card. The last step is requesting MT cars. For each business waybill generated by the computer which does not have an MT car available a MT request is placed in a rack at White Hall yard to instruct the yardmaster to locate and direct an MT car to that business. Waybills are not turned. When a car reaches its destination, either an interchange or business, the waybill is removed indicating the car has been unloaded. The car is then either loaded and another waybill is placed in its Car Card or it is directed to another business with an MT request or routed to its default MT location. Cars arriving at the interchanges are simply unloaded (waybill removed if one exists) and removed from the layout, only to return when the computer selects them again.

Staging the layout consist of three steps:



The first two steps are perform with the assistance of a Traffic Generator. This Traffic Generator controls the number of cars selected for each interchange, the load status of the cars and the destination of the cars. It also determines which E&P businesses will be shipping products and will need waybills and possibly MT car requests. It also determines when the private car is needed and when mail stops are needed at stations such as Flat Top where the Mail Express normally doesn't stop. All of this is control by probability number ranges and random numbers. When the generated random number falls within the probability range that record is selected for processing. The Car Table controls which cars will be place on one of the interchanges. The Business Waybill Control Table controls which business/car combinations will be generated for a shipment.