Create StationArrival[Index] Animated Variables

[leezer3]

Description

Request for two animated variables as per:

We probably need two more: arrivalNextStation departureNextStation

The supporting variables for these are already in place (e.g. stopsStation[StationIndex] etc.)

Other Considerations:

• Assume they should return 0 if not attached to a train.
• How should we handle non-stopping stations? Easiest way is probably to return a special value (e.g. -1) to indicate this, but consider carefully.
• Similarly, how do we handle terminal stations? Can probably use the existing terminalStation and then retain the same special value as per above, but would a different value be better?