13. Open Rails Sound Management

13.1. OpenRails vs. MSTS Sound Management

OR executes .sms files to a very high degree of compatibility with MSTS.

13.2. .sms Instruction Set

OR recognizes and manages the whole MSTS .sms instruction set, in a way generally compatible with MSTS. The differences are described below.

The Activation () instruction behaves differently from MSTS with regard to cameras (CabCam, ExternalCam and PassengerCam): in general OR does not consider which cameras are explicitly activated within the .sms files. Instead, it uses a sort of implicit activation, that as a general rule works as follows:

• when in an inside view (cabview or passenger view) the related inside .sms files are heard, plus all external .sms files (with the exception of those related to the trainset where the camera is in that moment): the volume of those external files is attenuated by a 0.75 factor.
• when in an external view all external .sms files are heard.

For an .sms file to be heard, it must be within the activation distance defined in the related instruction.

A hack is available so as to hear only in the cabview some .sms files residing outside the cabview trainset. This can be used e.g. to implement radio messages. For this to work the related .sms file must be called within a .wag file, must contain an Activation ( CabCam ) statement, and the related wagon must be within a loose consist, within a not yet started AI train or within the consist where the cabview trainset resides.

The ScalabiltyGroup () instruction behaves differently from MSTS for AI trains. While MSTS uses ScalabiltyGroup ( 0 ) for AI trains, OR uses for AI trains the same ScalabiltyGroup used for player trains. This way AI train sound can profit from the many more triggers active for AI trains in ORTS. For instance, Variable2 trigger is not active in MSTS for AI trains, while it is in ORTS.

If a Stereo() line is present within a ScalabiltyGroup, and a mono .wav sound is called, MSTS will play the sound at double speed. In order to have it play at the correct speed, a frequency curve halving the speed has to be inserted. OR behaves the same as MSTS in this case.

13.2.1. Discrete Triggers

Unlike MSTS, OR does not restrict the operation of some discrete triggers related to locomotives to the cabview related .sms file (usually named …cab.sms file). On OR they are all also active in the file related to the external view (usually named …eng.sms file).

OR manages the following MSTS discrete triggers:

Trigger	Function
2	DynamicBrakeIncrease (currently not managed)
3	DynamicBrakeOff
4	SanderOn
5	SanderOff
6	WiperOn
7	WiperOff
8	HornOn
9	HornOff
10	BellOn
11	BellOff
12	CompressorOn
13	CompressorOff
14	TrainBrakePressureIncrease
15	ReverserChange
16	ThrottleChange
17	TrainBrakeChange
18	EngineBrakeChange
20	DynamicBrakeChange
21	EngineBrakePressureIncrease
22	EngineBrakePressureDecrease
27	SteamEjector2On
28	SteamEjector2Off
30	SteamEjector1On
31	SteamEjector1Off
32	DamperChange
33	BlowerChange
34	CylinderCocksToggle
36	FireboxDoorChange
37	LightSwitchToggle
38	WaterScoopDown
39	WaterScoopUp
41	FireboxDoorClose
42	SteamSafetyValveOn
43	SteamSafetyValveOff
44	SteamHeatChange
45	Pantograph1Up
46	Pantograph1Down
47	Pantograph1Toggle
48	VigilanceAlarmReset
54	TrainBrakePressureDecrease
56	VigilanceAlarmOn
57	VigilanceAlarmOff
58	Couple
59	CoupleB (currently not managed)
60	CoupleC (currently not managed)
61	Uncouple
62	UncoupleB (currently not managed)
63	UncoupleC (currently not managed)

MSTS .sms files for crossings (crossing.sms), control error and permission announcements (ingame.sms) together with their triggers, and for fuel tower are managed by OR.

MSTS triggers for derailment are currently not managed by OR.

MSTS .sms files related to weather (clear_ex.sms, clear_in.sms, rain_ex.sms, rain_in.sms, snow_ex.sms, snow_in.sms) are managed by OR.

The signal file (signal.sms) and its discrete trigger 1 is managed by OR.

Moreover, OR manages the extended set of discrete triggers provided by MSTSbin.

13.2.2. OR-Specific Discrete Triggers

OR manages the following set of new discrete triggers that were not present under MSTS. If MSTS (or MSTSbin) executes an .sms where such discrete triggers are used, it simply ignores the related statements.

In addition, OpenRails extends triggers 23 and 24 (electric locomotive power on/power off), that were introduced by MSTSbin, to diesel engines. Keys <Shift+Y> (for diesel player engine) and <Ctrl+Y> (for diesel helpers), apart from physically powering on and off the diesel engines, trigger the above triggers.

Trigger	Function
101	GearUp : for gear-based engines, triggered by the <E> key, propagated to all gear-based diesel engines of a train and run also for AI trains
102	GearDown : for gear-based engines, triggered by the <Shift+E> key, propagated to all gear-based diesel engines of a train and run also for AI trains
103	ReverserToForwardBackward : reverser moved towards the forward or backward position
104	ReverserToNeutral : reverser moved towards the neutral position
105	DoorOpen : triggered by the <Q> and <Shift+Q> keys and propagated to the wagons of the consist
106	DoorClose : triggered by the <Q> and <Shift+Q> keys and propagated to the wagons of the consist
107	MirrorOpen : triggered by the <Shift+Q> key
108	MirrorClose : triggered by the <Shift+Q> key

Triggers from 109 to 118 are used for TCS scripting, as follows:

Trigger	Function
109	TrainControlSystemInfo1
110	TrainControlSystemInfo2
111	TrainControlSystemActivate
112	TrainControlSystemDeactivate
113	TrainControlSystemPenalty1
114	TrainControlSystemPenalty2
115	TrainControlSystemWarning1
116	TrainControlSystemWarning2
117	TrainControlSystemAlert1
118	TrainControlSystemAlert2

Triggers from 121 to 136 are used to synchronize steam locomotive chuffs with wheel rotation. The sixteen triggers are divided into two wheel rotations. Therefore every trigger is separated from the preceding one by a rotation angle of 45 degrees.

Triggers 137 and 138 are used for the cylinder cocks of steam locomotives:

Trigger	Function
137	CylinderCocksOpen : triggered when cylinder cocks are opened
138	CylinderCocksClose : triggered when cylinder cocks are closed

Triggers from 139 to 143 can be used to make looped brake sounds:

Trigger	Function
139	TrainBrakePressureStoppedChanging : for rolling stock equipped with train brakes, to use with triggers 14 and 54, triggered when the automatic brake pressure stops changing
140	EngineBrakePressureStoppedChanging : for locomotives with engine/independent brakes, to use with triggers 21 and 22, triggered when the engine brake pressure stops changing
141	BrakePipePressureIncrease : for rolling stock equipped with train brakes, triggered when brake pipe/brakeline pressure increases
142	BrakePipePressureDecrease : for rolling stock equipped with train brakes, triggered when brake pipe/brakeline pressure decreases
143	BrakePipePressureStoppedChanging : for rolling stock equipped with train brakes, triggered when brake pipe/brakeline pressure stops changing

Triggers from 150 to 158 are used for the circuit breaker sounds.

The following triggers are activated when the state of the circuit breaker changes:

Trigger	Function
150	CircuitBreakerOpen
151	CircuitBreakerClosing
152	CircuitBreakerClosed

The following triggers are activated when the driver moves the buttons or switches in the cab:

Trigger	Function
153	CircuitBreakerClosingOrderOn
154	CircuitBreakerClosingOrderOff
155	CircuitBreakerOpeningOrderOn
156	CircuitBreakerOpeningOrderOff
157	CircuitBreakerClosingAuthorizationOn
158	CircuitBreakerClosingAuthorizationOff

Trigger 161 is activated when the cab light is switched on or off.

The following triggers are activated when the state of the cab radio changes (see here):

Trigger	Function
162	Cab radio switched on
163	Cab radio switched off

The following triggers are activated when the state of the engines different from the first one change state in a diesel locomotive (see here):

Trigger	Function
167	Second engine power on
168	Second engine power off

13.2.3. Variable Triggers

OR manages all of the variable triggers managed by MSTS. There can be some difference in the relationship between physical locomotive variables (e.g. Force) and the related variable. This applies to Variable2 and Variable3.

New variables introduced by OR:

• BrakeCyl, which contains the brake cylinder pressure in PSI. Like the traditional MSTS variables, it can be used to control volume or frequency curves (BrakeCylControlled) and within variable triggers (BrakeCyl_Inc_Past and BrakeCyl_Dec_Past).
• CurveForce, in Newtons when the rolling stock is in a curve. Can be used for curve flange sounds, with two volume curves: one is SpeedControlled, which makes the sound speed dependent too, and CurveForceControlled. Of course CurveForce_Inc_Past, and CurveForce_Dec_Past are also available for activating and deactivating the sound.

13.2.4. Sound Loop Management

Sound loop management instructions are executed as follows by OR:

• StartLoop / ReleaseLoopRelease: the .wav file is continuously looped from beginning to end; when the ReleaseLoopRelease instruction is executed, the .wav file is played up to its end and stopped.
• StartLoopRelease / ReleaseLoopRelease: the .wav file is played from the beginning up to the last CuePoint, and then continuously looped from first to last CuePoint; when the ReleaseLoopRelease instruction is executed, the .wav file is played up to its end and stopped.
• StartLoopRelease / ReleaseLoopReleaseWithJump: the .wav file is played from the beginning up to the last CuePoint, and then continuously looped from the first to the last CuePoint. When the ReleaseLoopReleaseWithJump instruction is executed, the .wav file is played up to the next CuePoint, then jumps to the last CuePoint and stops. It is recommended to use this pair of instructions only where a jump is effectively needed, as e.g. in horns; this because this couple of instructions is more compute intensive and can lead to short sound breaks in the case of high CPU loads.

13.2.5. Testing Sound Files at Runtime

The sound debug window is a useful tool for testing.

13.3. Automatic switch and curve squeal track sound

With this feature a specific track sound is played when a train passes over any switch or crossover, or over a curve with a low radius, which highly enhances the sound experience. If this feature is enabled there is no more need to lay down specific sound regions around or sound sources above every switch or over curves. This is a lengthy task, and in fact most of the routes aren’t equipped with such sound regions or sound sources. Three automatic sounds are supported:

-  switch sound
-  curve squeal sound
-  curve + switch sound (when wagon is both on curve and switch).

It is possible to define also only one or two of these automatic sounds. If switch and curve squeal sound are defined, and no curve + switch sound is defined, the curve squeal sound is played when a wagon is both on curve and switch. The curve radius threshold below which the curve squeal sound is played is 350 meters for freight wagons and 301 meters for all other trainsets.

To enable this feature steps here below must be followed:

1. Suitable external and internal automatic sounds must be available (.sms files); usually you find them in the root’s SOUND. It often occurs that switch track and curve squeal sounds are available in modern routes. If not, they must be created or searched on the web. A test sound set may be downloaded from here.

2. For every route it must be checked whether a reference to the three automatic track sounds are present in the route’s ttype.dat file. If they are, you can proceed to next step. Else you must insert three new lines at the end of ttype.dat, adding the reference to the automatic track sounds, and you must add 3 to the number on top of the file. Here below an example of a default ttype.dat can be found, where three new lines referring to the above test sound have been added in last position:

   SIMISA@@@@@@@@@@JINX0t1t______
   
   13
   TrackType ( "Default" "EuropeSteamTrack0In.sms" "EuropeSteamTrack0Ex.sms" )
   TrackType ( "Concrete Supported"   "EuropeSteamTrack1In.sms" "EuropeSteamTrack1Ex.sms" )
   TrackType ( "Wood Supported"       "EuropeSteamTrack2In.sms" "EuropeSteamTrack2Ex.sms" )
   TrackType ( "In Tunnel" "EuropeSteamTrack3In.sms" "EuropeSteamTrack3Ex.sms" )
   TrackType ( "Steel Bridge" "EuropeSteamTrack4In.sms" "EuropeSteamTrack4Ex.sms" )
   TrackType ( "Girder Bridge" "EuropeSteamTrack5In.sms" "EuropeSteamTrack5Ex.sms" )
   TrackType ( "Under Bridge" "EuropeSteamTrack6In.sms" "EuropeSteamTrack6Ex.sms" )
   TrackType ( "Concrete Bridge" "EuropeSteamTrack7In.sms" "EuropeSteamTrack7Ex.sms" )
   TrackType ( "Crossing Platform" "EuropeSteamTrack8In.sms" "EuropeSteamTrack8Ex.sms" )
   TrackType ( "Wooden Bridge" "EuropeSteamTrack9In.sms" "EuropeSteamTrack9Ex.sms" )
   TrackType ( "Switch" "switchtrack7in.sms" "switchtrack7ex.sms" )
   TrackType ( "Switch" "DemoAutoSound/switchtrackin.sms" "DemoAutoSound/switchtrackex.sms"     )
   TrackType ( "Squeal Curve" "DemoAutoSound/curvesquealtrackin.sms" "DemoAutoSound/curvesquealtrackex.sms"   )
   TrackType ( "Squeal Switch" "DemoAutoSound/curveswitchtrackin.sms" "DemoAutoSound/curveswitchtrackex.sms"   )
   

3. For every route you must tell OR which of the ttype sound files are those related to automatic sounds. This is done by inserting following line in the route’s .trk file:

   ORTSSwitchSMSNumber ( 10 )
   ORTSCurveSMSNumber ( 11 )
   ORTSCurveSwitchSMSNumber ( 12 )
   

   A better solution, because it leaves the .trk file unaltered, is to create an OpenRails subfolder within the route’s folder, and to put in it an integration .trk file, named like the base one, and with following sample content (supposing the base .trk file is named ITALIA13.trk:

   include ( "../ITALIA13.trk" )
      ORTSDefaultTurntableSMS ( turntable.sms )
      ORTSSwitchSMSNumber ( 10 )
      ORTSCurveSMSNumber ( 11 )
      ORTSCurveSwitchSMSNumber ( 12 )
   

   Note that the above the include line a blank line must be present. Note also that with the same integration .trk file also the default turntable sound is defined, in case this route has turntables or transfertables.

   As already stated, you can also define in ttype.dat and in the .trk file only one or only two types of automatic sounds.

13.4. Override % of external sound heard internally for a specific trainset

External sounds are reproduced at a lower volume when heard within a cab or passenger view. The % of external sound heard internally is defined in the Audio Options menu window. This percentage may be overridden for any trainset inserting in the Wagon section of any .eng or .wag file (or in their “include” file as explained here) following line:

ORTSExternalSoundPassedThroughPercent ( 50 )

where the number in parenthesis may be anyone from 0 (nothing heard internally) to 100 (external sound reproduced at original volume).