Disturbances Design

Blockages Design

Track disturbances occur randomly in the game resulting in a tram track being blocked in a single location. At this instant, an ascending timer appears to indicate the elapsed time since the start, as an information for the player, also used for scoring purposes. It is to create a sense of urgency for the player and allow him to easily compare handling similar disturbances during gameplay. When a blockage appears the player needs to perform an action on it and possibly on the trams nearing it. If a tram is not stopped before the blockage by the player there is a small (5%) chance of it ramming the obstacle (or the tram ahead of it), resulting in penalty points. Otherwise it will stop on its own just before the obstacle. When an action on the blockage is performed, another, this time descending timer appears, indicating the time until the issue is resolved. However, some of the possible actions to perform have only a chance of success and take shorter time, other are certain but require more time. Moreover, the player is presented with other options, not suitable for this obstruction but still possible to choose from. In this case the timer also appears but when it has counted down, the blockage remains in place (similarly for right actions which were unsuccessful). There are no restrictions on how many times can a certain action be tried on the blockage. Whenever a player clicks on a blockage or a tram the game pauses until he chooses an action (or cancels). Trams can be stopped at any time and restarted as well, providing there is no blockage right ahead. When an issue is resolved, the trams will not proceed on their own, they need to receive a ‘go’ from the traffic controller (player). A desirable solution for blockage is rerouteing trams approaching the obstacle. Each of the trams needs to be rerouted manually and their paths can be different. Any affected by a blockage tram, should additionally be contacted to inform the passengers about the inconvenience. Providing information to unaffected trams yields penalty points due to confusion.

A list of possible correct actions for different blockages is presented below.

Blockages types:

Car (movable object) on tracks

Action	Probability of Success	Time Needed	Notes
Ask the tram driver to push the object aside	25%	10min	Works only with small objects. Requires a tram before the blockage
Use external horn repeatedly	10%	3min	Penalty points for passenger utility due to noise. Requires a tram before the blockage
Call towing service	100%	30min	Cost increase

Tree (stationery object) on tracks

Action	Probability of Success	Time Needed	Notes
Ask the tram driver to push the object aside	2%	10min	Works only with small objects. Requires a tram before the blockage
Wait for municipality services to deal with the problem	90%	45min	Costless but uncertain
Call for crane service	100%	60min	Cost increase

Damaged power line

Action	Probability of Success	Time Needed	Notes
Call for maintenance crew	80%	60min
Provide towing	100%	30min	Permanent speed reduction

Defective tram

Action	Probability of Success	Time Needed	Notes
Call for maintenance crew	90%	45min
Tow it with another tram	90%	15min	Requires two trams. Slightly unrealistic
Call for towing	100%	45min

Collision

Action	Probability of Success	Time Needed	Notes
Call for emergency services	100%	90min
Ask tram driver to request passage	20%	10min	Works only for minor collisions

Derailment

Action	Probability of Success	Time Needed	Notes
Call for crane service	95%	90min
Call for emergency services	100%	120min	In case of casualties

Defective line switch

Action	Probability of Success	Time Needed	Notes
Call for maintenance service	100%	45min
Ask drivers to switch manually	75%	15min	Permanently reduce speed in the section. Requires a tram before the blockage

Traffic lights failure

Action	Probability of Success	Time Needed	Notes
Call for maintenance service	100%	30min
Ask drivers to proceed carefully	100%	5min	Permanently reduce speed in the section. Requires a tram before the blockage
Ask for police assistance in traffic management	50%	20min