Part II
City placement
In Simutrans-Standard, cities are distributed evenly and randomly on the game terrain when a new game is first generated. A range of sizes of towns are automatically generated, but the only aspect of town size that the player can customise is the median size of the towns and the overall number of towns.
In Simutrans-Extended, there are additional options to determine the number of very large cities in comparison to the ordinary size of towns, to set cities in clusters, for towns to tend to be built more on lower ground than higher ground and for towns to be more likely to be built near rivers and the sea. Also, there are more likely to be rivers generated on high ground, increasing the total number of rivers generated. Most of this feature (with the exception of towns preferring to be built at a lower height) was written by Inkelyad.
The aim of these features is to enable a more realistic and interesting landscape to be generated, to allow, for example, river transport in times before canals or the grouping together of large urban areas whilst still allowing wide open spaces.
City size distribution
In Simutrans-Standard, cities are sized more or less randomly based on a median set when generating the game.
In Simutrans-Extended, city sizes are set according to Zipf's law (http://brenocon.com/blog/2009/05/zipfs-law-and-world-city-populations/) of city size distribution. The code for this feature was written by Richard Smith.
The aim of this feature is to make the landscape on which players play more realistic.
Note: As of circa 2017, this feature has been noted not to be working correctly. It is planned to fix this when town generation/growth is rewritten.
Liveries
In Simutrans-Standard, each type of vehicle has only one appearance, except that it can have different graphics for being empty or carrying different loads, if applicable.
In Simutrans-Extended, vehicles can have different liveries. Liveries are grouped in livery schemes (in each of which, there can be multiple liveries according to date, so that, for example, the scheme "British Railways" can have the liveries "BR Early", "BR Revised", "BR Blue", "BR Large Logo", etc.). Players can select which livery scheme applies to vehicles when bought in a depot, and can additionally re-assign livery schemes to lines.The aim of this feature is to improve the visual representation of historical vehicles over time. This feature has no economic effect.
Bridges and elevated ways
In Simutrans-Standard, bridges can have length and height restrictions, but these are optional. Height restrictions do not discriminate between height above and below water. Where the overall length of a bridge is not restricted, it is possible to build a bridge over a large stretch of open ocean. Further, elevated ways can be built over buildings of any height.
In Simutrans-Extended, bridges with unlimited length cannot be built over deep water (that is, water more than 1 tile below sea level). Further, elevated ways can only be built over buildings of a size of no greater than 2, and larger buildings cannot appear under existing elevated ways.
The aim of this feature is to prevent players building very long bridges over open seas which would not be possible to build in reality, at no greater cost than building bridges on land, which can distort water transport, and further to impose realistic restrictions on the use of elevated ways in heavily built-up areas, confining them to the suburbs of larger towns and cities, and providing incentive to use (more expensive) underground railways instead.
Terraforming
In Simutrans-Standard, it is possible to raise and lower land anywhere (with the exception that one cannot start raising/lowering land in open water). This allows even deep oceans to be bridged with artificial embankments.
In Simutrans-Extended, it is not possible to raise land - even indirectly by raising its neighbours - when it is more than 1 tile below sea level.
The aim of this feature is to prevent players from circumventing the challenge of dealing with seas and lakes by turning them into land.
City roads
In Simutrans-Standard, players are free to delete any city roads without restriction. This allows players to leave large numbers of city buildings disconnected from the city road network when building their networks. Further, players are allowed to build private roads in cities, which remain private and inaccessible to any other player's transport. The city speed limit is a hard-coded 50km/h.
In Simutrans-Extended, players may not delete city roads such as would leave city buildings disconnected from the city. Any road built in a built-up area of a city will be adopted by the city authorities and available to use by all players. The city speed limit will apply, and the city will pay for the maintenance of the road. The city speed limit is the speed limit of the current city road as defined by the pakset's simuconf.tab.
The aim of this feature is to require players to respect the integrity of cities when planning networks, so that players have to work around features already present rather than simply overriding them, and also to prevent players from unrealistically increasing the speed limit in built up areas or from excluding players from cities with private roads.
Settings overriding
In Simutrans-Standard, game settings are specified for new games in the configuration file simuconf.tab. When a game is generated, these values are saved in the saved game, so that, even if simuconf.tab is later changed, the settings in a game already created remain the same. These can, however, be changed using an the advanced settings GUI dialogue for each individual saved game.
In Simutrans-Experimental, it is possible to specify a simuconf.tab parameter (progdir_overrides_savegame_settings=1) to allow some settings in simuconf.tab to override settings in any saved game loaded when that parameter is so set. This does not affect online games, which will always load all of their settings from the saved game downloaded from the server.
The aim of this feature is to permit easier changing of saved game settings on previously generated saved games using simuconf.tab. This feature was entirely written by Nathaneal Nerode.