Railway Signals
Railway signals allow multiple trains to use the same tracks by dividing them in shorter rail sections, or blocks. Before a train enters a block, it looks up whether the track it uses in that block is already reserved by another train. If it is not, the track in that block gets reserved and the train enters. Otherwise, the train will just wait at the entrance of that block until it is empty. Note: Trains will not attempt to change their route if they encounter an occupied block, even if there are empty parallel tracks. Note: Trains do not reserve blocks, but the tracks within them that they will use. There can be multiple trains in one block.
In order to place a signal on your track, first choose a signal in your track menu. The buttons look different depending on the pakset in use:
Upon selecting the signal, your mouse courser changes to indicate that you are now placing signals.
Click on a piece of track to place your signal. You cannot place a signal on an intersection or on a piece of track with a different signal already in place. For most signals, you will now see a signal on both sides of the track. This is called a bidirectional signal, because it works the same in both direction. If you keep clicking, you first get monodirectional signals and then a bidirectional signal again. Monodirectional signals work in one direction only, while they block all traffic in the other direction.
You can also use drag to place many signals along the track at once. To do that, hold the control key while clicking on the signal to open a window called "Set signal distance".
The signal spacing is defaulted at 2, which means a signal is placed every second tile. This allows trains to move in succession with only 2 tiles distance between them. Since such a dense succession is usually not required and each signal costs some Credits, especially in the beginning a higher spacing is recommanded. You can choose to remove intermediate signals and replace other signals. The first option removes all signals in the gaps between newly placed signals, the second replaces signals which happen to be in a postion where a new signal would be planted. It's usually best to leave both activated. When you place signals using dragging, they are all monodirectional in the direction you dragged. However, you can't drag past monodirectional signals in the other direction. This allows for a little trick:
Place two parallel tracks and connect them at the ends. Place one monodirectional signal to indicate the direction in which your signals should be placed (A), then drag from the tile behind the monodirectional signal (B) to the tile in front of the signal (C) to place them over the complete track. To finish off, delete the manually placed signal (D).
Note: While signals work the same for all kinds of tracks (eg. normal gauge, narrow gauge, monorail, maglev,...) you cannot place a track signal on a monorail track or vice versa.
The most common signal, called basic signal, block signal or just rail signal in different paksets, is used as a seperator between blocks. Upon approaching a basic signal, a train will reserve the the piece of track on it's route up to the next signal, or up to the next station it will stop at, whichever comes first:
##Pre-Signal/Two-Block Signal
Upon approaching a pre-signal, a train will not only check up to the next signal, but up to the signal after the next signal. In other words, the train checks two blocks instead of one.
Like with the basic signal, a station at which the train stops will end the check prematurely. It does not matter in which of the two blocks the station is placed.
##Long-Block Signal
The Long-Block Signal is used in a bottleneck situation, when two or more stations are placed along a single track, but there are many trains using it. Normal signals would only check up to the station they want to arrive at, so it would be possible for both stations to be occupied with trains going in opposite directions, blocked by each other. A deadlock the player needs to resolve manually.
Upon arriving at a Long-Block Signal, a train will check up to the next signal, regardless whether there are stations inbetween or not. If the way is free, it then reserves up to the station. This is enough, since a train from the other direction will now see the reserved track and not allow another train to enter the bottleneck.
Make sure that all tracks leading to the bottleneck use a Long-Block Signal, and no other signals are placed anywhere in the bottleneck (eg. no signals for a multi-platform station inbetween)
(i) missing on github
##Platform Choose Signal
(j) missing on github
The platform choose signal, or just choose signal, can be used to allow trains to automatically choose an empty platform at a station. Upon arriving at a choose signal, a train will check whether the platform chosen in its schedule as well as the route to go there is empty. If it is not, the train will check all other platforms to see if there is one available (platform + route to go there), and use that instead. If there is no alternative available, the train will wait at the signal until the scheduled platform is empty and will not attempt to route to another platform again. Be careful not to create situations where a platform is reachable, but only over a long detour. Trains are not smart enough to recognize that, they would go across the map and back if that's a way for them to reach a platform. Also, never place a choose signal at a drive-through station if not every train stops there. Trains will understand it as a choose signal for their destination, however far it might be. If the train does not get stuck right their, it will reserve the complete route to it's destination, blocking all other trains from using it. This does usually not result in a deadlock, so there might not even be a notice about stuck trains.
End of Choose Signal, shortly EoC, sometimes more precisely called 'Exclude from Platform choice', allows exactly that. When a train at a choose signal is searching for possible other platforms, it will see this EoC-signal as if it was a barrier and not attempt to go through it. Note that it does not actually exclude a platform from the search, but the track to reach it. Because of that, if there is a route to 'excluded' platforms which does not lead over an EoC-signal, the train might take it.
This signal is always monodirectional and forbids vehicles to pass in that direction. However, it does not seperate blocks, so it can be used in conjunction with Long-Block signals.
Player Gates are always bidirectional. They exclude all other players from using the piece of track it is buildt on. Clicking on the gate with the view-tool allows the owner to change who is allowed to pass it. If you are allowed to pass the gate, it will appear open to you. But if you are not allowed to pass, it is closed.