Path signal setup

Since the introduction of single track in version 1.2 and path signals in version 1.2.22, it is now easier to recreate real life railway lines in the game. This guide aims to create a set of best practices focusing on path signal setup for different scenarios that can be found in real life.

Path signals are set to prevent collisions of trains. They occur when a train runs into the side of the other train, or when a train runs head on into another train. Note that trains running into another train from the back is not considered as collision in this game.

The basic idea is to setup path signals at points where trains enter a collision area and setup balises at points where they exit that area.

Collisions

There are three ways collision can occur.

Merging collisions

Merging collisions can occur when tracks merge into each other. This can be resolved by adding path signals on the tracks entering the collision area and block balises on tracks leaving that area.

Crossing collisions

Crossing collision can also occur when tracks crosses each other. Same as before, this can be resolved by adding path signals on the tracks entering the collision area and block balises on tracks leaving the area.

Note that technically the above collisions can resolve itself without the need of path signals when the blocking train moves away from the collision area.

Head on coliisions

Head on collisions occurs when trains runs on a single track facing each other. Here we arrive at problems that are truly blocking, as they can't resolve itself and path signal alone will not resolve the problem. Path signals will need to work with track designs in order to allow the trains to work around each other.

Junctions

Junctions are location in the tracks where trains switch branches or crosses each other. The simplest forms are the ones mentioned above, where it can also be as complicated as a grand union junction, an example of which can be seen in Streetcar tracks between Bathurst Street and King Street West[www.google.com] in Toronto.

However the signalling approach is still the same as above. Add path signals on tracks entering the collision area and block balises on tracks leaving the area.

Double / Multi tracks terminals Station terminals can cause head on collisions that when trains reach the end of a railway line, they enters into a station platform and will have to reverse out of it to start another trip on the railway line.

System default terminus

When building stations in double track mode, by enabling "Auto append scissor intersections and path signals for double platforms":

We arrive at the default setup for terminal stations.

When focused on just one side of the station, it is now a terminus. In this setup, Signal A is the Entry Signal, Signals B and B' are the Platform Exit Signals, and Signal C is the Exit Signal. Trains arriving at the station (A) can reverse at either platforms and leave via the exit (C). When other trains enter to the station they are stopped by the Entry signal (A) if the destination platform is occupied.

It is recommended to also enable "Auto append direction signals" when building the default terminal stations as it allows the two tracks exiting the station to be bi-directional.

It is recommended change the Entry signal (A) to type AB type signal in order to limit the path lookup for the Platform Exit signals (B and B').

This type of setup are used in real life mostly in rapid transit terminals, such as Fish Creek-Lacombe station[www.bing.com] of CTrain in Calgary.

System default through terminal Through terminal can be archived when both side of the stations are used. Trains arriving at the station from the west (A) can stop at the platform (B or B') and exit either east (C) or west (D) Platform Exit signals must be set to only bounding same directional (Type DB or DS) in order for the Entry signals have path that goes through the platforms.

Multi-track terminus

Increasing number of platforms to a terminus can allow more railway lines to operate at it. The path signaling is just the same as the system default one, where the Platform Exit Signals should be Type DB and the Entry Signals should be Type AB signal.

Do not put any signals in between the two sets of signals as this will break the line of path when lookup and can cause collisions.

In real life, multi-track terminal stations are built as starting point of regional rail services in cities such as Helsinki Central Railway Station[www.bing.com]

Multi-track through terminal Multi-track through terminals provide a flexibility of railway operation for both through traffic and terminus railway lines.

When signalling for through terminals: Once again, the path signaling is just the same as before, Type AB signals are setup for Entry Signals (A & H), the Platform Exit Signals should be Type DB (B & C), and the Exit Signals are Block Balises (D & G)

Here we have an option at specifying through only platforms (platforms C, D, E, & F) by using One Way signals on them.

In real life, through terminals are usually built at cities where railway line passes through. Examples of these terminal includes the Chiayi railway station[www.bing.com]

Local and Express services When running both local and express services on the same track, when signals are not placed in the passing stations, the Express service will not leave the signal until the path in front up until a signal or station is clear.

Therefore it is recommended to put in Type DB signals along the tracks and stations, essentially breaking them into multiple signal blocks. This can increase throughput along the lines.

Passing tracks In order for the Local services to not block the Express services, passing tracks can be built for the express services to run around the station platforms. In this setup, Signals A and B are the Platform Exit Signals, and Signal C and D are the Exit Signals, and Signals E and F are the Exit Block Signals.

If you want to make the Local services always wait for the Express services to pass, you may want to remove the Exit Block Signals (E & F) all together.

This track layout is used intensively by high speed rails to allow local and express services. Examples of these stations includes the Shin-Fuji station[www.bing.com]

Single tracks rail lines Edit Single track rail lines can easily create head on collisions as it has trains running in both directions on a single line of tracks.

They can occur when trains go past their terminal and reverse for the next operation. Here are some examples.

Single reversing track

Here trains leaving platform C will not enter the Y section until it is cleared.

It is optional to move the signal from point C to B, both yielding same operation. Or you may put in signals at both points if your section between point B and C are long enough to hold a train.

In real life, single reversing tracks are used at terminal stations for rapid transit where high frequency is required and where there might be no plan to further extend the line or space is limiting. Reversing track to the west of Kennedy Town station[www.openrailwaymap.org] is one example.

Double reversing tracks

Double reversing tracks allow the turn back operation to have even higher frequency and a flexibility of train storage.

Here trains leaving platform C will not enter the X section until it is cleared. If the terminal has 2 lines terminating, setup signals at both point B and B' and use waypoints to separate the traffic between the two tracks for higher throughput. Do not put signal at point C, otherwise trains waiting for platform A to clear will block the cross for the reverse tracks to be used by the other line.

In real life, single reversing tracks are used at terminal stations for rapid transit where high turn around is required and reverse plan to further extend the line. Track section to the west of Zhangguozhuang station[www.bing.com] is one example.

Pocket track

When trains are required to terminate and reverse service on a through line, a pocket track can be used.

It is essentially a reversing track in between through lines. Remember to set the signal at point B to not bound paths from other direction (Type DB) in order for path lookup at point A to look through the reversing tracks. It is optional to move the signal from point D to point C (or to be removed all together) for the through tracks to have higher priority.

Examples of such setup can be found usually on rapid transit lines that provide short turn services, tracks on the west of Northolt station[www.google.com] is one example.

Single track lines

If a rail line has only a single track throughout, only one train can operate on it and therefore signals are only used to protect other trains from entering the single track section for turn around. In cases where the line has only 2 stations, the signal at point A can be Type DB or Type AB

Shuttle service between Mill Hill East and Finchley Central[www.bing.com] can use the above configuration.

However if there are more than 2 stations along the rail line, the signal at point A must be Type DS or Type AS in order for the path look pass the stations.

Rail lines such as St Ives Bay Line[www.openrailwaymap.org] operates in such a manner.

St Ives Bay Line[www.openrailwaymap.org]

Passing loop

To allow more than 1 train to operate on a single track, passing loops are built to allow trains travelling in opposite directions can pass each other.

The loop can be built in track sections or at stations. Make sure that all the signals before a train enters the single track section must be set to Type AS in order for the path to look beyond the next station and stops path lookup from opposite signals.

In track passing loops are usually used in funicular railways such as The Fribourg funicular[www.google.com].

In station passing loops are usually found in railway lines that predates modern signaling as it is where the signalling token are handed over from the train leaving the single track section to either the station or onto another train entering that section. Stations such as Shifen station[www.bing.com] can use the signal configuration above.

Switchback railways

In situations where trains need to climb steep gradients, switchback operations maybe used such that trains will travel in reverse after passing a switch onto another section of gradient.

Although the path indicator when building the signals will show that the path ends at the switch

The actual path lookup will treat the tracks as a single track and reserves track ahead of it.

Therefore same as a regular single track rail line, if there are stations along the single track sections, the signals in front of the single track section will need to be of Type AS

Examples of these includes the Alishan Forest Railway [www.openrailwaymap.org]

Conclusion Edit The introduction of path signals together with single tracks are great improvements for this game as it allows real life railways to be more accurately represented. Also shown in all the examples above, the Simple block signal is now obsoleted and should be replaced by path signals.

Please let me know if you think there are other examples that should be included in this guide. Thank you for reading, and thank you to Weird and Wry for creating this game to fulfill our dream of train modelling the world!