Track

Planimate® supports modelling of railway type networks with a set of related features collectively known as “Tracks”.

Tracks modelling capabilities are considered to be advanced uses of Planimate®, and require a good grounding in and familiarity with the concepts underlying the Planimate® Platform as a whole.

A “Track” is a Planimate® object, along which items can travel, taking a designated period of time.

Tracks are placed between Portal Objects (representing depots, terminals, crossing loops and junctions). Tracks connect together the subsystems of these Portals. An Item can leave a subsystem, travel across a Track object and some time later arrive in the subsystem at the other end.

Similar to Spatial Links, Tracks offer an opportunity to display and animate transport networks, where Portals represent nodes in these networks. However, Track Objects differ to Spatial Links because their carrying capacity is limited.

Track Capacity

The capacity of a Track Object can be set between one and three. A Track shows its capacity by displaying one, two or three lines. Only one item at a time can travel along an individual line (or ‘Road’) of a Track. Supporting features enable Track capacity and allowable direction of travel to be manipulated and adjusted before or during a model run.

Routes

By default, an item will use flow paths in its movement through a Planimate® system model. To make an Item use a Track network, the item is given a “Route” to follow. A “Route” comprises a list of locations that are to be visited in turn, travelling along Tracks instead of Paths.

Once an item commences a route, it looks up a table to determine how long it is to take travelling across each Track “section’.

Traffic Control in Tracks

When the links in a transport network (as well as the node points) have limited capacity and many items are moving along their routes across the transport network, traffic conflicts arise. This can become quite complicated to manage so Planimate® provides built-in supporting logic to assist with successfully managing traffic conflicts. This “Track Control Logic” logic provides “common-sense” checking that reduces (but cannot totally eliminate) the chance of traffic becoming ‘deadlocked’ and unable to move.

Broadly, before letting an item enter a track, Planimate® performs checks to ensure that the item is: a) free to move to its next point of capacity, which is often located in the subsystem at the other end of the track, but could in fact be a few subsystems and track sections ahead, and b) unlikely to cause trouble for other item movements elsewhere on the network if it moves along the track.

Planimate®’s built-in Track Control Logic is often all that is required to ensure that traffic movement is continuous and the movements collectively are “reasonable” in terms of the waiting times experienced by the individual items in making their way along their routes. Sometimes however, special cases or particular circumstances in the system being modelled mean Planimate®’s built-in logic does not resolve traffic movements to the modeller’s satisfaction. In these cases, the modeller is able to ‘hook into’ the internal logic and inject conditional tests etc which will produce the desired outcome.