Elvas Tower: Maximum Speeds and Consists - Elvas Tower

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Maximum Speeds and Consists Thoughts about setting the Maximum Speed for a Train Rate Topic: -----

#21 User is offline   darwins 

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Posted 07 May 2020 - 05:20 AM

Quote

Sound to me like this would be covered in the special instructions or timetable.
That would make it the responsibility of the engineer and conductor to know the speed limit of their train based on the consist.
Trackside speed limit signs and signal aspects will tell you the track speed permitted, the paperwork will tell you how fast you can go.
How do you simulate that.

The answer is that we have the F4 HuD to simulate that (plus sometimes written instructions in activities). F4 and F5 is our paperwork and our route knowledge and our train knowledge.

If I have a 90 mph locomotive and a set of 100 mph coaches running on a 110 mph route, I want the F4 HuD to display 90 mph as the permitted maximum speed.If I then attach a van that has a maximum permitted speed of 45 mph to the same train the F4 HuD should change to display 45 mph.
At the present this is impossible as MaxVelocity for the F4 HuD comes only from MaxVelocity in the .con file (or the top of the column in a time table file).

#22 User is offline   steved 

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Posted 07 May 2020 - 09:27 AM

If the sim gets it's speed limit from the .con file why wouldn't the correct speed be in there?
That would work up until the point when you set out that crane that's been holding you to 20mph, then you can go track speed.
Seems ORTS would have to scan the .wags and .engs and keep track of the MaxVelocity allowed.
I'm asking because I'm learning, just like everyone else.
Thanks
Steve


#23 User is offline   darwins 

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Posted 07 May 2020 - 10:11 AM

I have dozens of .con files with incorrect maximum speeds in them.

Why?

Because either myself or some other person who assembled the consist could not be bothered to put the correct speed in!

Probably more likely that people would enter the correct data when creating locos, carriages and wagons - but then again may be not.


OR is in any case constantly scanning the wag files in the player train for a lot of information - this is not likely to be very heavy on computing power.

To be genuinely realistic there might need to be other rules added for the maximum speed for consists - either player or AI. For example locomotives when running light engine are often required to run at lower speeds when they would when pulling a train - usually I believe for reasons of fuel economy.

On my part I am putting out a suggestion for improvement (over what we had in MSTS). There might be better suggestions for improvement out there. Keep things the same because it works really well is a good answer too. I am bit disappointed with keep things the same because that is the way they are though.



#24 User is offline   atsf37l 

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Posted 07 May 2020 - 11:39 AM

View Postdarwins, on 02 May 2020 - 12:14 PM, said:

My understanding is

MaxVelocity in eng files only affects performance of MSTS files and does not set a speed limit as such.
MaxVelocity in wag files is not currently valid in OR.

The only valid way to set a speed limit in OR is using the consist file in activity mode and explore mode, or using an equivalent in the timetable column in timetable mode.
Attaching or detaching vehicles does not change the speed limit. (Nor in activity mode can you set a speed limit for a light engine, which will be lower than the speed limit for a train it will subsequently pull.)
In timetable mode if attaching or detaching changes the speed limit for the train then it needs to form a new train in a new column.


I would disagree. MaxVelocity does indeed set the speed limit for the particular locomotive. Where is this useful? Let's say I'm running a Santa Fe 3700 Class 4-8-2 on the "Scout" out of Winslow, Arizona. In real life, 3700-3750 had a system wide speed limit of 70 MPH. I picked up my engine on the ready track at Winslow, hooked up to a 'powerless' consist at the depot and headed off for Gallup, New Mexico on track which has a speed limit of 90 MPH. The powerless consist should have a zeroed out MaxVelocity statement, because I can hook a switch engine or a big high-speed 4-8-4 or a brace of EMD FT's to the consist. If the MaxVelocity statement of 70 MPH is not in the .eng file on my 3700 then when I switch control to OR's Autopilot the whole shootin' match jumps to 90 MPH!

With the MaxVelocity in the .eng file set at 70MPH the loco will top out around 69.8 regardless of the 90 MPH track speed.

Same can be said for freight operations where the track speed is set for the Super Chief but my 3160 class Mikes with 63" drivers should roll along at a top speed of around 45 MPH. Activities which start off as light engines need MaxVelocity to set a reasonable speed for freight operations using player control or Autopilot.

Thus my 2 cents. :bigboss:

#25 User is offline   cr-stagg 

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Posted 07 May 2020 - 11:55 AM

Let me offer some comments Concerning the MaxVelocity Field in Consists files. Some background. I worked on the ConBuilder team from version 1.8.1 through version 6.2.3. ConBuilder's code was originally developed Mr. Carlos Gomes and he wrote it to mimic MSTS. It did in most ways except for the MaxVelocity parameters in Consist files. Carlos coded ConBuilder to enter the default values of ( 40.0 and 1.0000 ), but he also provided a tool for the user to enter the values and when the CON file was saved either the default or the user's values were saved in the file.

Sometime after Carlos left the ConBuilder team and shortly before it became payware I began working with the MSTS CE to reverse engineer how the MSTS CE calculated the two values. Then I developed the code specifications so that ConBuilder would calculate the values and enter them in the file when the CON file was saved. Also a recalculation was implemented when an existing CON file was edited and saved.

The MaxVelocity value is the MaxVelocity from the ENG file of the lead engine in the Consist in meters per second and the second is a factor for acceleration. I will not reveal what the logic and calculations are used for the acceleration factor as it is much more complicated and could be Considered proprietary to ConBuilder; and because this is a discussion of velocity and speed limits not acceleration.

Also during this reverse engineering research, it was found/confirmed that MSTS (the Sim) does not use the MaxVelocity values from the Consist file for the Player Consist physics, but does use them for the Traffic (AI) Consists. How ORTS uses (if it even does use) the MaxVelocity factor values from CON file I do not know. Probably 5 years ago or more I asked the developers that question and was told ORTS does not use those values but calculates the capability of a Consist by examining the components. That makes sense: as player Consists can change during an activity and any traffic Consist can become the player Consist. However, the ORTS manual in section 10.12 seems to indicate otherwise. Perhaps it was later decided to use the values.

There was a comment in this thread about "wagon MaxVelocity". Kuju/Microsoft did provide some documentation on ENG and Wag files and distributed them with the MSTS CDs. That document defined MaxVelocity within the Engine Section. ENG files are composted of a Wagon section and an Engine section. WAG files only have Wagon sections. There is not an Engine section in WAG files. Therefore, there are no MaxVelocity parameters in WAG files. If ORTS were to have a capability to utilize the parameter for wagons, then it would need to be done as an "ORTSMaxVelocity".

Throughout this thread there seem to be a misunderstanding of definition of terms and an equating of Maximum Velocity and Speed Limit. Also, section 10.12.3 in the ORTS Manual sees to suffer the same malady. It also appears that the author of this section thinks that the values of the MaxVelocity parameter in CON files are actual values as in MPH or m/s/s instead of factors.
Maximum Velocity describes a physical capability. Speed Limit is and arbitrary restriction imposed by administrative means. Example I could drive my car down the street in front of my house at 60mph or faster, but the city has imposed a Speed Limit of 25mph. The MaxVelocity parameter in ENG files given in MPH or KPH is the physical capability of the locomotive based on many factors. It is generally ascertained from manufacture's documentation. MaxVelocity physical capability of wagons may have been documented or specified by their manufacturer, but there is not a Parameter for them in WAG files. Equating these numbers to Speed Limits is nonsense.
While looking at the manual I notice a comment about ORTS applying an efficiency factor to the acceleration value in the CON file MaxVelocity. My reverse engineering determined that the MSTS CE applied an 80% efficiency to the acceleration value when it was calculated. ConBuilder’s code does this also. So if another 80% is applied then Traffic Consists in ORTS would accelerate 80% slower than the same Consist in MSTS.

One last comment about ConBuilder Concerning the version 2.4.9 which is in the TS library here. It is the last free ware version and still inserts the default ( 40.0 1.000 ) values in CON files.

#26 User is offline   atsf37l 

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Posted 07 May 2020 - 10:12 PM

Charles I'm a little confused about the way you say ConBuilder builds a consist file. I just created a consist file for a lite 60 Class D&RG 2-8-0 a couple of days ago, accepting the default values. Here's how it reads:

SIMISA@@@@@@@@@@JINX0D0t______

Train (
TrainCfg ( D&RG203Lite
Name ( "D&RG 60 Class 203 Lite" )
Serial ( 1 )
MaxVelocity ( 0.00000 0 )
NextWagonUID ( 3 )
Durability ( 1 )
Engine (
UiD ( 1 )
EngineData ( 60_class_d&rg_203 60_Class_D&RG_203 )
)
Wagon (
WagonData ( 60_Class_D&RG_203_tender-OR 60_Class_D&RG_203_tender )
UiD ( 2 )
)
)
)

MaxVelocity ( 0.00000 0 ).

Maximum speed for this loco either for "overspeed" indicators or Autopilot running is the 17 MPH specified in the MaxVelocity statement in the .eng file.

Conbuilder 6.1.2. So I don't understand what you're saying about the calculations involved with the default save??? :huh: :bigboss:

#27 User is offline   atsf37l 

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Posted 07 May 2020 - 10:32 PM

Continuing, and I hate to stir it up but I just went into ConBuilder and built a light consist for 203's sister, 226. I elected not to accept the default just to see where it would take me and I noticed this is for a "durability factor:"
Attached Image: Clipboard01a.jpg

Leading you to a parameters selection screen:
Attached Image: Clipboard01.jpg

Having nothing to do with MaxVelocity at all?????

And what, exactly, is a "durability factor?" :curiousPC:

#28 User is offline   steamer_ctn 

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Posted 07 May 2020 - 11:27 PM

View Postatsf37l, on 07 May 2020 - 11:39 AM, said:

With the MaxVelocity in the .eng file set at 70MPH the loco will top out around 69.8 regardless of the 90 MPH track speed.
Thanks for confirming my suspicions.

As part of some OR code review on diesel locomotives this is the MaxVelocity parameter that I would like to get a consensus on what to do with it.

In the current code for a BASIC configuration (ie no TF curve table) , once the max velocity figure (in eng file) is reached the TF is set to zero. For an ADVANCED configuration (ie with TF curve tables), it will be as per the modellers configuration of the table.

As best as I can make out in real life, typically the TF does not appear to go to zero in a single step, rather the value decays as the speed increases past the max velocity, and the power decreases accordingly. So I believe that to set a zero step decrease at max velocity is incorrect. I can understand this happening if there was a TCS which trigger a power shutdown.

So the question is, again in real locomotives, what speed does MaxVelocity equate to? Is it the "maximum design speed"? Secondly what happens when this speed is reached, does TF go to zero, does it decay, or are the traction motors and gearing transmissions destroyed because of over speed?

I think that the two MaxVelocity values need to be treated as different values as follows:

i) MaxVelocity (ENG) - this is a performance parameter in terms of what the locomotive is capable of. It should not be an operational parameter. For example the locomotive might be capable of performing at a high speed, but for a specific operational requirements the railway company will set a lower operational speed.

ii) MaxVelocity (CON - or wherever) - this is an operational parameter and as such should be treated differently to the value above, and depends upon train operational requirements rather then train capabilities.

Does anybody know whether the TCS system can "cut power" above certain speeds? If so, in the BASIC configuration, I would like to change the OR code so that above the MaxVelocity (design speed) the TF ramps down, rather then going straight to zero. The TCS could override this as a monitoring safety measure.

Thoughts?

#29 User is offline   darwins 

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Posted 07 May 2020 - 11:30 PM

The discussion about conbuilder is interesting.


I will take an example for how I set values in consist files when writing an MSTS activity.


Let us consider a train of say 30 unbraked mineral wagons with grease axle boxes hauled by a 2-8-0 locomotive.


The eng file says MaxVelocity ( 60mph ) the kind of speed those engines achieved pulling passenger trains on summer Saturdays.


So assemble to consist in conbuilder or MSTS Activity Editor and it comes back with something like MaxVelocity ( 26.8224 0.4212 ). What we have now is a high speed mineral train!


Not a problem we know a bit about railways, and we know that no one is going to let wagons with heavy loads, no train brakes and grease axle boxes zoom around at more than 25 or 30 mph. So we manually edit the maximum speed of our consist. 25 mph is 11.2 m/s so we might put a value of 12 into the consist file. (Not too precise in this case as it was before the days of speedometers being fitted to locomotives!) Now we have MaxVelocity ( 12 0.4212 ).


The next step is to test it out in an activity editor (Autopilot) run through. We want to know does the AI train keep to sectional timings over our route. We test it out and find that even though we have reduced the Maximum Speed of the train, it is still arriving at its destination far too early. Perhaps we should not be so surprised, the calculation in AE or conbuilder is probably assuming that it is a diesel loco that can work constantly at full power and that it has air brakes that can stop in a fairly short distance. Getting power from a guy shovelling coal and stopping 600 tons with a steam brake are not the same thing. So we do some trial and error with our Autopilot and find that the train keeps to the timetable with the value of MaxVelocity ( 12 0.28 ).


I was hoping that OpenRails would make the whole process easier. It seems everything is just the same.


This also highlights the fact that the maximum permitted speed shown in the F4 HuD is based only upon line speed and locomotive - ignoring any speed limits due to the rolling stock. So to avoid offending the purists here what I am suggesting is that we allow the option, in the wag section of any eng or wag file to add a new parameter - ORTSMaxPermittedSpeed ( x ) that will be used by the F4 track monitor and for also for AI trains to limit their maximum speed.

#30 User is offline   darwins 

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Posted 07 May 2020 - 11:50 PM

Quote

Does anybody know whether the TCS system can "cut power" above certain speeds? If so, in the BASIC configuration, I would like to change the OR code so that above the MaxVelocity (design speed) the TF ramps down, rather then going straight to zero. The TCS could override this as a monitoring safety measure.

The answer is yes. This is from an MSTS default loco:
	OverspeedMonitor(
		MonitoringDeviceMonitorTimeLimit( 0 )
		MonitoringDeviceAlarmTimeLimit( 5 )
		MonitoringDevicePenaltyTimeLimit( 0 )
		MonitoringDeviceCriticalLevel( 151 )
		MonitoringDeviceResetLevel( 0 )
		MonitoringDeviceAppliesFullBrake( 1 )
		MonitoringDeviceAppliesEmergencyBrake( 1 )
		MonitoringDeviceAppliesCutsPower( 1 )
		MonitoringDeviceAppliesShutsDownEngine( 0 )
		MonitoringDeviceTriggerOnTrackOverspeed( 1 )
		MonitoringDeviceTriggerOnTrackOverspeedMargin( 2 )
		MonitoringDeviceResetOnZeroSpeed( 1 ) 
		MonitoringDeviceResetOnResetButton( 0 )
		)

So long as you include MonitoringDeviceAppliesCutsPower( 1 ) then if you exceed the maximum speed you will lose power, you can set the maximum permitted speed for this such as MonitoringDeviceCriticalLevel( 125mph ) and you can do some or all of the other things in the TCS monitor or not as you wish.




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