Disturbances Design

From this design we start implementing the following:

Blockages : Car, switch, derailment, defective tram.

Incidents : Woman in labour, angry mob

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 (happens only to trams on the map or depots)

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 (happens only to trams on the map)

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 (happens only to trams on the map)

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

Driver unavailable (only in depot)

Action	Probability of Success	Time Needed	Notes
Call for additional driver	80%	30min	Extra cost
Cancel tram	100%	10min	Resulting in points penalty

If the next tram does not stop before the blockage and rams into it, the situation escalates. Next to significant penalty points there are other consequences listed below:

Blockage	Primary Result (chance)	Secondary Result (chance)	Notes
Car (movable object) on tracks	Derailment (50%)	Collision (50%)	Depending on severity
Tree (stationery object) on tracks	Derailment (70%)	Collision (30%)	Depending on severity
Damaged power line	Derailment (75%)	Defective tram (25%)
Defective tram	Derailment (90%)	Collision(10%)
Collision	Derailment (90%)	Collision (10%)
Derailment	Derailment (90%)	Collision (10%)
Defective line switch	Derailment (100%)	-
Traffic lights failure	Collision (50%)	No consequences (50%)

Note that tram ramming another tram in front of it is always treated as tram running into a defective tram and it is not possible to ram into a tram in a depot.

Tramcar incidents

Tramcar incidents are limited only to the trams and are introduced to increase the variety in the game, so that the players do not continue to face the same problems all the time. They are, nevertheless, of lower importance than the blockages. Incidents occur randomly throughout the game and need to be dealt with as soon as possible. If a correct action is chosen by the player, it is awarded by extra points. If an wrong action is chosen, the player can repeat his choice after 5min without a direct penalty. However, if the situation is not resolved after an hour, it may escalate into a bigger problem. Yet, if it is solved before that, there is no impact on tram operations and the player is awarded with extra points. Below, a set of possible tramcar incidents is shown, along with correct advices of the traffic controller to deal with the problem are shown:

Drunken passenger

Action	Notes
Stop the tram and ask to leave	One needs to restart the tram manually

Angry mob

Action	Notes
Call the police

Woman in labour

Action	Notes
Call an ambulance

Passengers in distress

Action	Notes
Calm them down

Fire on board

Action	Notes
Extinguish it with a hand extinguisher

Air-gun firing at tram

Action	Notes
Call the police

Stench on board

Action	Notes
Ventilate the tram

If the right action is not performed and the one hour limit reached the situation has always 50% chances of escalating into something serious. On top of that, there is always a score penalty for not dealing with the issue. Below, a table of possible consequences of not solving certain tramcar issues is shown. It is not limited to tramcar incidents but also includes blockages.

Incident	Primary Result (chance)	Secondary Result (chance)	Notes
Drunken passenger	Passengers in distress (70%)	Angry mob (30%)
Angry mob	Passengers in distress (40%)	Defective tram (60%)	Depending on severity
Woman in labour	Passengers in distress (100%)	-
Passengers in distress	Angry mob (100%)		Repeating cycle of losing points
Fire on board	Passengers in distress (50%)	Defective tram (50%)
Air-gun firing at tram	Passengers in distress (90%)	Angry mob (10%)
Stench on board	Passengers in distress (70%)	Angry mob (30%)

It should be noted, that the “Angry mob” incident is considered most severe and not dealing with it is punished with the highest point penalty.

Rerouteing and tram stops

At any given point in the game the player is able to change the route of a single tram. If multiple tram paths are to be altered, the player needs to do this manually for each of them. There are no predetermined consequences of altering tram paths. Tram stops, however, need to be visited every given fixed period of time. Regular setting without disturbances has predefined tram routes that fulfil that requirement but altering routes can complicate that. The player needs to make sure that all stops are visited within that given time and if not, he is will start losing point for every real-time second when the stop is not visited after the period from last visited tram has passed.

Travel information

Informing travellers of possible delays or difficulties is a vital part of every traffic controller’s job. After all, it is all about the passengers. Thus, in case of a blockage and rerouteing the player needs to choose affected stations and perform “Inform passengers” action that is the same for all blockages. The challenge is to only perform this action on affected stations, since choosing wrong one results in travellers’ utility score penalty, bigger than the added points for selecting the right one.