Automatic merge of T1.5.1-870-ge0bf062eb and 18 pull requests

- Pull request #570 at 3539862: Experimental glTF 2.0 support with PBR lighting
- Pull request #839 at d00beb9: First phase of https://blueprints.launchpad.net/or/+spec/additional-cruise-control-parameters
- Pull request #876 at f92de76: docs: add source for documents previously on website to source Documentation folder
- Pull request #882 at 9c456aa: Blueprint/train car operations UI window
- Pull request #885 at 8f94333: feat: Add notifications to Menu
- Pull request #886 at 6c0785b: Scene viewer extension to TrackViewer
- Pull request #892 at 1f5ba4c: Signal Function OPP_SIG_ID_TRAINPATH
- Pull request #896 at 5866028: First implementation of https://blueprints.launchpad.net/or/+spec/specific-sounds-for-ai-trains
- Pull request #897 at 42f1dd9: feat: Improved system information collection
- Pull request #903 at 0d6d045: Downloading route content (Github, zip)
- Pull request #907 at 9b0b04f: Bug fix for https://bugs.launchpad.net/or/+bug/2047300 Dynamic tracks disappear after long tunnel
- Pull request #911 at 6834af0: docs: Add refactoring as a special type of PR
- Pull request #912 at 659396e: New Triple Valve Features Vol. 2
- Pull request #914 at ab5ea99: Adjustments to Duplex steam
- Pull request #915 at 6d911d7: Correct calculation error with curve friction
- Pull request #916 at 11ac52c: Distributed Power Air Brake Synchronization
- Pull request #917 at fde18cf: Lighting Configuration Enhancements
- Pull request #918 at f7ba507: Manual - News topics updated since 1.5.1

Author: openrails-bot

Source/Documentation/Manual/physics.rst

@@ -4478,6 +4478,60 @@ drag constants are used in calculating the still air resistance, then it might b
 inputting these values.
 
 
+.. _physics-track-sanding:
+
+Track Sanding
+=============
+
+Sanding of the track is required at times to increase the wheel adhesion.
+
+Open Rails supports air and steam operated track sanders which consume air or steam and sand. Typically 
+OR has standard defaults which it uses to allow track sanding to operate, however if the user knows the 
+actual values for the locomotive that they are modelling then they can override these values by entering 
+the following parameters in the engine section of the ENG file. Note - if values are not known then it is 
+highly recommended that the default values be used.
+
+When using any of the following parameters, the sanding system type needs to be set by allocating either "Steam" or 
+"Air" to the ``SandingSystemType`` ( x ) parameter in engine section of file.
+
+**Steam Consumption**
+
+``ORTSMaxTrackSanderSteamConsumptionForward`` - total steam consumption for all sanders when traveling in 
+forward direction, ie in front of wheel.
+
+``ORTSMaxTrackSanderSteamConsumptionForward`` - total steam consumption for all sanders when traveling in 
+reverse direction, ie behind wheel. Note, = 0 when not used.
+
+All steam consumption parameters are in lbs/sec.
+
+For steam sanding there will be a visible presence of steam when the sander is operated, this steam effect 
+can be added by using one or both of the following aparmeters.
+
+``SanderSteamExhaustForwardFX`` - steam effect when travelling forward, ie in front of wheel.
+
+``SanderSteamExhaustReverseFX`` - steam effect when travelling in reverse, ie in behind the wheel.
+
+**Air Consumption**
+
+``ORTSMaxTrackSanderAirConsumptionForward`` - total air consumption for all sanders when traveling in reverse 
+direction, ie behind wheel. Note, = 0 when not used.
+
+``ORTSMaxTrackSanderAirConsumptionForward`` - total air consumption for all sanders when traveling in forward 
+direction, ie in front of wheel.
+
+All air consumption parameters are in cuft/sec.
+
+**Sand Consumption**
+
+``ORTSMaxTrackSanderSandConsumptionForward`` - total sand consumption for all sanders when traveling in forward 
+direction, ie in front of wheel.
+
+``ORTSMaxTrackSanderSandConsumptionReverse`` - total sand consumption for all sanders when traveling in reverse 
+direction, ie behind wheel. Note, = 0 when not used.
+
+All sand consumption parameters are in cuft/sec.
+
+
 .. _physics-trailing-locomotive-resistance:
 
 Trailing Locomotive Resistance