Layers tab question

A complicated question with no simple answer.

In short it lets you add layers to a layout and/or session, similar to the layers in most paint programs. Route layers, for example, can contain different scenery items, session layers can have different rolling stock items.

There are limitations and pitfalls and many Trainzers hate or love the layers.
How about editing? When I make a new session in my route. Nothing appears but ballast & I need to merge the route layer with the session & vice versa or not?
One of the major misunderstandings (and problems) people have with layers occurs when they are loading and saving their routes and sessions. Understanding the difference between loading/saving sessions and loading/saving routes is crucial.

In Surveyor open the LAYERS Tab and you will see a section labeled Route (for all the route layers) and another labeled Session (for all the session layers). A brand new route will always have a starting route layer and a starting session layer. You can add, delete, rename any of the layers and you can merge any of the layers within a group (e.g. within the Route layers or the Session Layers) or between the two separate groups. If you merge all the session layers into a route layer or delete the only remaining session layer and then save, when you reload the layout and re-enter the Layers Tab you will still see a route layer and a session layer.

In a nutshell.

  • The landforms, water, sky, painted textures and perhaps a few other things are stored in a route file (not a layer).
  • Rules (eg driver commands, driver setup, and any other rules you have added) and the properties of interactive industries (including passenger active stations) are saved with a session (but, apparently, not in a session layer).
  • Apart from the above, everything else goes into route and/or session layers (but see pointers below)

But a few important pointers:

  • It is very very strongly advised that you place all track assets; track, rail bridges, tunnels, signals, speed signs, switches, etc; into the same route layer and preferably the one at the top of the list.
  • Other scenery items can go in route and/or session layers (see example below)
  • If you are going to create several different scenarios for your route then place the rolling stock in a session layer.

For example, you are going to use the same layout with two different scenarios, one that concentrates on passenger operations and another that concentrates on freight operations. All track assets should be placed in the top route layer, as mentioned above. All scenery items that will be common to both scenarios (and that would be most of them) should be in a route layer - you can put them all in a new layer to make them easier to manage or leave them in the top route layer with the track assets. Some creators, for example, place all their trees in a tree route layer (no pun intended).

Place your rolling stock for the passenger scenario into one session layer and name it P-Stock (names used here are examples only). Any scenery items that would only be needed for the passenger scenario (eg extra cars parked at a station) place in another session layer and name it P-Scene. Save the route (giving it a name) and the session (name the session Passenger Ops).

Then edit the rolling stock in the P-Stock layer to change it to the rolling stock required for the freight scenario or delete the layer and start a new one and add the freight rolling stock. Rename the layer to F-Stock.

Edit the items in the P-Scene layer (eg remove most of the cars at stations and add trucks at the industries, etc) or delete it and start a new one with the new freight scenery assets. Rename the layer to F-Scene. [IMPORTANT] Use Save or Save As to create a new session and name it Freight Ops, do not change the route name.

Exit Surveyor and return to the Routes list. You will still see the route listed with its original name. Select the route and click View Sessions. You will see two sessions listed - Freight Ops and Passenger Ops.

From this point on when you want to edit one of these scenarios, Select the Route, then View Sessions, then Select and Edit the particular session.

If you are not confused at this point, then I will continue.

When you are editing a scenario (eg Passenger Ops), any changes you make to a session layer will only affect THAT scenario (eg. add a new consist, change a drivers command list, add a new product to an industry, add more cars to the session layer parking lot). Any changes you make to a route layer will affect BOTH scenarios (e.g. move a signal, junction or track segment, add more trees to a route scenery layer). If you want to make changes to the route by editing one of the route layers then it does not matter which scenario you load for your editing.

If your editing has only altered assets placed in the session layer group, then when you save you only need to save the session - select the Overwrite Existing Session save option Trainz will offer to you. If you have edited assets placed in the route layer group, then you will need to save the route - select the Overwrite Existing Route save option.

I generally advise against loading and editing the route by itself (without loading a session) unless you know what you are doing - it can easily lead to a disaster.
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Layers only contain scenery objects (like buildings, tracks, rolling stock,...). Other things like landscape, groundtexture or rules are not a part of any layer. The landscape and groundtextures are saved in special files with the route. Rules are saved as data with the sessions. The properties set using the ? dialog of scenery objects used to be saved with the sessions (one exception the name). Starting with TS12 the current properties were additionally saved with the route, everytime the route was saved, becomming the default values for any new session.

I stand corrected - my info is obviously a carry over from early versions of Trainz. But my essential rule of thumb remains the same - "always edit the session not the route".
@ pware: A small correction - You start post #4 by saying: "Go into the Sessions Tab" but this should have been "the Layers tab".

I agree largely with your reasons for saying "always edit the session", but there are cases when it is better to edit the route. This applies more to route-builders rather than session planners, who do their work after the route is "finished". In all cases it is necessary to ensure that you know which layer you are working on.

Work done on the wrong layer can be corrected by addressing each item on the properties pane and changing the layer to which it belongs. Junction levers should always be placed on a route layer otherwise they can fail to show the green arrow when resuming a saved game.

I believe that the layer feature was first introduced in order to overcome a problem when creating a session for a route on the DLS, that is, to be able to add extra trackmarks and other trackside objects to the session without modifying the route; something which could not be done before layers existed.

There are some strange features of layers, one of which is the ability to drag a layer from route to session and back. This is useful if you have placed a number of new items such as rolling stock in a session and you need then to be present in a different session. Instead of having to add them all over again into the new session you can move them into their own session layer and then drag the layer to the route panel. You can then load up the other session and drag the rolling stock layer back the the session panel.

Doing this can cause havoc if you are not careful. Best practice is to save your original route and sessions in separate cdp files before starting so as to be able to recover if a mistake has been made.

Best Regards

Thank you Trevor, correction made. I confess I was typing my reply from a computer that did not have Trainz (of any colour) installed so I was working from memory.
Vary good info on a somewhat complex subject. It would be nice if that could be put into the Wiki.
So, I put the track, signals, triggers, grade crossings in a separate layer, roads in a separate layer, & trains, rolling stock, etc. in separate layers in the session tab then?
You can put them all in the same route layer if you want to. It depends on how complex your plans are for using the layout. If I am going to create a layout with just a single scenario then that is what I do but I usually create multiple scenarios based on the same layout - that is where the session layers become useful.