The special ground effects layers Clutter and TurfFX that are available in the Topology Tools (press the  F1  key) are not discussed here. They are more like Textures than Layers but some aspects of their use and operations are similar to the layers covered here. These special ground effects layers are saved as part of a Route but are not associated with any Route Layer.

• The first image on the left gives an example of the layers that can appear if a Route only is loaded into Surveyor. These are the layers that are saved with the Route. Note that a default "session-layer" is present.

	An empty default "session-layer" is always created in the Session Layers Group when only the Route is loaded into Surveyor.
	If you load just the Route and edit its "session-layer" then those edits will not appear the next time you load just the Route because an empty "session-layer" is created each time a Route is loaded without a Session.

• The second image on the left gives an example of the layers that can appear if a Session based on that Route is loaded into Surveyor. It shows Route Layers and Session Layers.
  
  

In both cases, the Route Layers are identical because the same Route has been loaded. A Session contains its own layers, the Session Layers, that are loaded and saved with the Session but are not loaded or saved with the Route.

If you load a Session and do not want to edit any of the Route layers then click the Lock Route Layers icon on the Layers Tool Click the Lock Button

The Active Layer is the "working layer" which is:-

• where new objects will be added to the layout
• the layer that is automatically selected for merging and deleting

• Deleting a layer will delete ALL the objects placed in that layer except objects that are "Bound" to that layer. See The Bound Layer section below.
• In TRS19 (all versions) and Trainz Plus there will be a delay when deleting a layer. The delay will be indicated by a progress bar but can take several minutes on very large routes.  Resist the urge to click the Cancel button . This delay will occur every time a layer is deleted.
• Due to a "bug" deleting a layer that contains a ruler will not delete the ruler. It will be hidden from view but it may reappear if another layer with the same name as the deleted layer is created or it will, eventually, reappear in the route-layer.

• The first image on the left shows two Route Layers, both UNLOCKED with their Padlock icons Open. One layer, "Trees", is highlighted showing that it is the currently active layer.
• The second image on the left shows the same two layers after the "Trees" layer has been LOCKED.
• A locked layer can be UNLOCKED by clicking its Closed Padlock icon.
  
  

• Click the icon to UNLOCK the layer

• within the same layer group (e.g. Route or Session)
• between the two groups

In TRS19 (all versions) and Trainz Plus there will be a delay when moving a layer. The delay will be indicated by a progress bar but can take several minutes on very large routes.  Resist the urge to click the Cancel button . This delay will occur every time a layer is moved.

	Steps: Select the layer to be moved and hold down the left mouse button Drag the layer up or down to its new position

• The move can be between layer groups as shown left or within groups to move the layer to a higher or lower position in the group.
• The only situation where layer order within a layer group makes any difference is when adding track objects (e.g. signals, track signs, etc) to a track.

	When adding track objects to a track, the object being added must be in the same layer or in a layer below the layer containing the track. For more information, see the section The "route-layer" below.
	If you attempt to move a layer containing track objects, such as signals, to a position above the layer containing the track, you will get an error message.

• In the image shown left the two trees are in different Route Layers
• All the layers have their Eye Icons set to Show

• In the image shown left the Trees layer has its Eye Icon set to Hide
  
  

	If you attempt to add an object to a hidden layer you will receive a warning message.
	Layers that are hidden when saved in Surveyor will also be hidden when loaded in Driver.

• For a Route with only a single Session - everything can safely go into the Route Layers Group

Many creators only ever build a single Session for each of their Routes and do not use Session Layers at all (but they still have to save the session separately from the route).

• For a Route with multiple (2 or more) Sessions - certain things will probably need to go into the Session Layers Group for each Session.

Many creators build multiple Sessions for each Route and rely on the Session Layers to create the differences between their Sessions.

• Many scenery assets actually have their properties stored in the Session, even when the assets themselves are in a Route layer. Editing the properties of these assets is considered to be a change to the Session. Unless you have a particular reason for saving the edited data (such as a change to commodities) you can usually ignore the offer to save the Session. These assets include:-
  • junction switches - the left/right switch direction is stored in the Session (but the default direction is stored in the Route)
  • industries - the commodities and quantities loaded/unloaded are stored in the Session
  • industry enabled wagons - the commodities and quantities carried are stored in the Session
  • consist locations (TRS19 Platinum Edition and Trainz Plus only) - this is stored in the Session (unless you need to save their new locations, you can safely ignore the offer to save the Session)
  • named route objects (TRS19 Platinum Edition and Trainz Plus only) - while the name is stored in the Route, adding or changing the name is treated as a change to the Session

• The recommended practice in these versions of Trainz is to place all consists in a session layer and NOT in a route layer. Because these versions use a Unified Driver Surveyor, placing a train in a route layer after switching from Driver to Surveyor can cause problems. For example:
  • If active Driver consists (i.e. those under manual or AI control) are in a route layer and you switch from Driver to Surveyor to edit the route and save the route edit, then those consists will be saved in their new positions, not their starting positions for the session.
• Recent experiments using the Unified Driver Surveyor have indicated that when portals produce trains they will be placed into the same layer as the portal - so if a train that is in a Session layer enters a portal that is in a Route layer and is later returned to the layout, it will be returned in the same Route layer as the portal. This has possibly always been the case with portals but has not been noticed until the arrival of the Unified Driver Surveyor

• It is a good idea to place ALL the consists in the same layer particularly if they are going to be coupled together during the running of a Session.
• A very useful development tool is the Bound Layer. See The Bound Layer section below.

• Track and interactive industries with track
• Track infrastructure (turntables, bridges, tunnels, etc)
• Signals and track signs (speed limits, warnings, distance, etc)
• Junctions and switches

Session Layers can contain:-

• Scenery objects that will only appear in one or some of the Sessions.

For example: If you have placed human figures and equipment for a track work crew alongside the track and want them to be seen in a daylight Session but not in a night Session, then place them in one of the Session Layers of the daylight Session only. Likewise, station staff holding lamps would be placed in one of the Session Layers of the night Session only.

• Consists used in a Session.

• It is a good idea to place ALL the consists in the same Session Layer and using a Session Layer for ALL consists is the recommended method for Trainz Plus. Particularly if they are going to be coupled together during the running of a Session.
• When you first save a Session, give it a distinctive and informative name. Avoid the temptation to use Default as the name of your Session as you can easily end up with several Sessions under the same Route all called Default.

• Click the icon to UNLOCK the layer.

There are many features of Trainz Routes and Sessions that are NOT stored in layers. These include:-

Landforms, textures, TurfFX, Clutter and trackside cameras are saved as part of the Route while all the others are saved as part of a Session.
^ A bug has been reported in the Interlocking Towers (and the Enhanced Interlocking Towers) where the path and settings are initially saved in the Route but any later edits and changes are then saved in the Session. The workaround for this is to always load the Session when working with ITs and EITs. This problem has still not been fixed in TRS19 SP2.

• It is good practice to LOCK ALL LAYERS that you are not currently editing. This will avoid the all too common problem of accidentally deleting objects from the wrong layer.
• An exception to this "good practice" is when managing rulers. Unless you have used a dedicated ruler layer for all rulers it can be difficult to discover which layer contains a particular ruler. If rulers are not added to a dedicated layer then you will need to unlock and unhide all the layers first before you can use the Delete Ruler tool.

• that the objects layer and bound layer (if set) are unlocked
• that you are using the correct delete tool (e.g. such as attempting to delete a tree with the spline, signal or rolling stock delete tool) - it happens!

• Create a new empty layer called "Locked" or "Hidden" and lock or hide that layer, according to your needs
• Bind the individual objects to that layer as required
• When editing, testing or whatever you are doing has been completed simply delete the new layer. All objects that have been bound to that layer will have their Bound Layer property reset to none so the hidden objects will reappear and the locked objects will be unlocked.

• In the first image on the left, all layers are visible
• In the second image on the left, two of the layers have been hidden

More Tutorials and Guides to Using Trainz

• How to Guides
• Driver Commands List
• Session Rules List (Alphabetical) with Parameters
• Session Rules List (Categories) With Parameters