Signalling in Simutrans Extended is intended to be more realistic than in Standard, and faithfully recreate the evolution of railroad signalling from the early 19th to the early 21st century. This page will explain the basic concepts.

If you're new to signalling in Extended, you might want to watch this series of lovingly produced HiQuality tutorial videos:
Video Tutorials for the new Signal system on the SimEx YouTube channel

For a list of simulated signal types, their years of availability and working methods, see:
Signal Types in the current Pakset

For a list of signalboxes, their years of availability and signals they can control, see:
Signalboxes in the current Pakset

For a list of signs and their functions, see:
Signs

Signals overview

Since the dawn of railways, the biggest problem has always been to ensure that two trains are not running into each other. This has resulted in the development of various safety systems, rules, technical safety instruments etc.

The most important concept is that trains can reserve a block of rail (one or more tiles). No train can enter a tile which is already reserved by another train. A reserved block can be only a single tile ahead of a slow-moving train driving by sight, with no signals being used. Or a train can reserve several kilometers of line between two signals. Tile reservations are cleared when the train has passed a reserved tile.

The only signal you can place without a signalbox is the One-train-staff signal. Most signals do not show up in the toolbar until you have placed a signalbox on a tile next to the line (except the One-train-staff signal and signs, like End-of-choose or Private Way, which are always visible. Signs in the game are not true signals; they modify the behaviour of a train, but trains do not stop at them).




Signals do not show up in the toolbar until you have placed a signalbox.

Note that all signals and signalboxes become available in a certain year and month, and many become obsolete and therefore unavailable later. Existing signals can be used indefinitely, though. Also note that there is usually a maximum allowed distance between signal and signalbox, as well as a maximum number of signals that can be controlled from a single box.

Tram and Narrow gauge railway signalling works similarly to train signalling.

Press "B" to see reserved tiles. This can be very helpful when trying to understand what your trains actually do. The cursor also switches to "Block Reservation" mode. While in that mode, click a reserved block to delete that reservation.

Sighting distance

The traindriver can only see a certain distance in front of the train. The sighting distance is heavily used when driving by sight (check Signals working methods) but is also used to determine the speed that a train is approaching an upcoming signal. Since the train does not know the state of an upcoming signal, it must drive slow enough in order to be able to stop in front of the signal. However, this can be improved by using presignals, which will tell the driver at a much earlier point, at what state the signal is, so the driver doesn't necessarily have to brake at all.

Directional reservations

It is possible to create a directional reservation. That is a reservation of the tracks in a certain direction, and represented with the color BLUE with the block reservation tool. A directional reservation can only be created by placing bidirectional signals that uses certain working methods.

Read more about how to use them here: Signal Types

Unidirectional signals

Signals are unidirectional signals that do not prevent trains passing in the opposite direction. Trains passing in the opposite direction will ignore the signals completely. Some signals using certain working methods can also be built as bidirectional signals, controling traffic from both directions and thus creating directional reservations.

Signal spacing help window

Ctrl-click on a signal icon in the toolbar brings up this window. Click-and-drag on track brings preview of signals to be built, release the mouse button to build. Signals will be built allowing trains to pass only in the direction you dragged the mouse.

In network games: first ctrl-click on the track and release mouse button. While you hold down mouse button and move the mouse, you see preview. Release button again to build.

Parameters in this window:

- Signal spacing: how many tiles apart consecutive signals should be placed (diagonal count as 1/2 tile). This value is shown on the icon if the signal is selected.
- Remove interm. signals: if toggled, other signals on the way will be deleted.
- Replace other signals: if toggled, other signal on tiles we would like to build our signals on will be deleted.

These parameters can be set for all different signals independently.

Working methods

Signals are working with so called working methods, which will determine how the signal will behave and how the train will reserve the track beyond the signal. Different working methods represents different real life rail systems, and there are different signals available to the various working methods. From early 19th-century flag signals to modern electronic cab signalling, it's all in the game.

Read more about working methods here: Signals Working Methods

Signalboxes

A signal can't just be built as a standalone signal: They need signalboxes in order to be built. A signalbox is in the real world the shelf or the building from which the signals are controlled. Newer techniques allows for more efficient signal systems with greater numbers and more remote controlled signals. In Simutrans, different signalboxes allows for different signals, simulating the different eras and techniques.

For a list of signalboxes, their years of availability and signals they can control, see: Signalboxes in the current Pakset

Multiple aspect signals

A signal may have up to 5 aspects, in addition to aspects for permissive signals and choose signals showing alternative routes. Not all paksets make use of all of the aspects and the graphics of the signals might be very different between paksets.
The core function of such signals is to rize the density of the tracks. The more aspects, the smaller blocks of tracks one can create without compromizing with lower top speeds, thus creating room for more trains on the tracks. Therefore, the most effective way of using multi aspect signals are at lines with a big traffic demand.

Read more about how to use them here: Signal Types

Sighting speeds

At higher speeds, signs and signals get more difficult to read. Each signal has a maximum sighting speed (defined as "Max speed") which is the maximum speed that the traindrivers human eye can read the messages given from the signal. In effect, this means that a train will not pass a signal at higher speed than the signals maxspeed. Although with modern technology cab signalling allows the signal states to be shown inside the cab of the trains, thus allowing for a higher sighting speed, as it is the technology that "sees" the signal.

Choose signals

Choose signals serve two functions: They will guide the train to an empty platform at the station, and they will guide a train through a station, also if the mainline route is occupied.
To make use of this second function, you need to place an end of choose sign outside all the exits of the station. When a train aproach the choose signal, it will be given a route all the way till its destination or the "end of choose" sign, whichever is encountered first.

Read more about how to use them here: Signal Types

Permissive signals

Permissive signals are used to increase line capacity. When a train is brought to a stand at a permissive signal at danger, it may proceed beyond the signal at "drive by sight". This is only possible where the signal controls a section of straight, unidirectional track. If there are junctions, the permissive functionality is disabled and the signal works as an ordinary signal.

Read more about how to use them here: Signal Types