An alternate routing is executed if the destination for its primary routing has no capacity for additional entities. The alternate routing is created when you connect a line from a routing (the primary routing) to the alternate destination as illustrated below.
If capacity is unavailable at the alternate destination, the entity is routed to the first destination with available capacity. DO NOT attach more than one alternate to any routing so that it is always clear which routing is the alternate. However, an alternate routing may itself have an alternate routing; as many alternate routings as needed may be defined.
Action logic on a route will only be executed when an entity actually traverses that route. Therefore, in an alternate routing situation, action logic on the primary route will not be executed if the entity selects the alternate route. However, if a resource “connector line” is attached to the primary route, and the resource is not available, entities will be blocked from selecting either the primary or the alternate route. When a resource connector line is used, the resource must be available before any other actions can occur on the object’s capacity (route, activity, or storage).
Usage
Simple directional decisions based on no room at the destination are made with the alternate routing
Type Any routing connected from another routing must be an alternate, so this field cannot be changed.
Move Time This allows you to specify a different move time for the alternate routing. Any expression is valid.
- An alternate routing may be used with the following routing types:
DO NOT use an alternate routing with an Attach , Ordered , or Pickup routing. Instead, use the Else routing with these signal activated routings.
Example
Military aircraft land for refueling and are directed to a series of hydrants (which is the fastest method of refueling). If all of the hydrants are full then the aircraft is diverted to a series of large fuel bladders. If all of the fuel bladders are being used the aircraft is sent to a parking spot where trucks fuel the aircraft. Refueling by truck is the slowest method of refueling and thus selected only when the other options are not available.
Alternate routes are drawn by selecting the line connector tool 
and drawing from an existing route to a destination activity or storage.
Routing Types
The following routing types are available: