[darwins]

As OpenRails develops further it seems that some of the MSTS engine controllers are limiting our ability to represent real life controls.

Work on brakes has produced several new train brake tokens, which now make it possible to model almost all of the common brake controllers. Even then the only way to get "sprung" notches is using a script such as: ORTSTrainBrakeController( "PBL2BrakeController.cs" )

Is this going to be the answer to other control problems and do there need to be standard scripts available for these?


Reverser

UK diesels have an "Engine Only" position that is distinct from "Neutral". Something I am now thinking about with regard to slow speed control where disengaging slow speed seems to involve closing the throttle moving the reverser from "Engine Only" to "Forward" and opening the throttle again.

DirControl ( 0 -1 EO 1 1 ) seems more appropriate than DirControl ( -1 0 1 1 )

Similarly for a steam (or power) reverser we should have "sprung" or "while pressed" type of control, something like

Cutoff ( -0.75 0.75 0.01 0 NumNotches( 3 )
Notch ( 0.0 0 IncreaseCutOff )
Notch ( 0.5 0 HoldCutOff )
Notch ( 1.0 0 ReduceCutOff ) )

which is not yet possible.


Gears

There are a lot of possible "gear" changes for mechanical and hydro-mechanical transmissions that can not yet be represented. Some examples:

0-1-0-2-0-3-0-4-0-5-0-6 where there is a neutral step between each gear as in some early mechanical gearboxes.

R-0-1-0-2-0-3-0-4 a road gearbox having a reverse gear with a different gear ratio to the forward gears.

0-4-3-2-1 gears in the reverse order as in the Wilson epicyclic gearbox.

0-D a neutral or drive selector used with some automatic gearboxes.

0-C-D neutral - converter drive - direct drive selector used on manual hydromechanical transmissions.

Some "transmission" functions were also added to throttles.


Throttles

As mentioned above transmission functions added to the throttle.

0 - "set up" - 1 - 2 - 3 being used on the Budd RDC railcars and their Australian descendents with the "set up" position being used to fill the torque converter prior to moving off.

0 - 1 - 2 - 3 - 4 - "lock up" was used with some British hydromechanical transmissions, with the "lock up" allowing converter drive to continue to a higher speed before changing to direct drive.

There is a great deal missing in terms of throttles for electric traction.

Locomotives with tap changer control usually had a throttle that had

OFF - RUN DOWN - NOTCH DOWN - HOLD - NOTCH UP - RUN UP

Scripts have been made to do this for some locomotives. It would be good to develop those so that they could be used by everyone and for locomotives with different numbers of transformer taps. Some locos had weak field notches in addition to transformer taps. IIRC these had to be selected after the top notch and would not automatically be reached by RUN UP.

Similarly for Electric Multiple Unit throttles from days gone by, the variations of the Sprague automatic controller all allowed the train to "notch up" automatically, however it was never possible to notch down, you have to first move the controller to OFF and then select the lower power.

Even with steam the twin port regulator is missing. Certainly with the MR / LMS version of the regulator closing and opening were different - so if you wanted to judge the regulator opening you were advised to close the regulator and then open it again.

[scottb613]

Hi Darwin,

Along these lines - a cause which I've tried to champion for years - we really need HID or Joystick or Analog input device compatibility. This is 2022 after all.

Analog devices are a solution to having proper response from controls - you can't do the same with emulating keyboard presses no matter how hard you try.

Binary keyboard presses introduce lag and lack precision.

The sim is aware of the exact position of an Analog device.

Analog devices are cheap and widely available in a myriad of configurations.

Analog devices would greatly increase operation and immersion of ORTS.

Regards,
Scott

[ErickC]

I can think of a few things:

• I think a delay timer for the throttle would be handy. In real life, notching up is not instantaneous - there is a slight delay between moving the handle and the locomotive responding. We should be able to set this delay (in seconds). Note that this delay should only occur once when advancing the throttle multiple notches.
  
  
• It would also be nice to have a control setup for locomotives using a combined throttle/dynamic brake handle with a selector switch, as was common in the first generation of diesel locomotives. Utilizing the combined control setup simply does not work for this because the combined control logic is based on modern locomotives with a lever that stops in a neutral position, then continues in the same direction for braking. This is problematic for several reasons:
  
  
  • Retarding the throttle to idle often leads to accidentally placing the locomotive in set/up for dynamic braking. This is simply incorrect for a first-generation locomotive, where the throttle cannot be used for dynamic braking until the selector switch is placed in dynamic braking mode.
    
    
  • The operation of the throttle in dynamic braking is in the same direction as ordinary power (see: CSX 8888 incident, 1969 SP Cuesta derailment), but the throttle is not notched when in dynamic braking mode. The obvious solution would be to parent the throttle to a dummy part that is animated appropriately for dynamic braking, but due to a bug in the way OR handles animations, any sub-object of an animated part will only animate with the parent part (e.g., animated wipers that are a subobject of a door will not animate when the wipers are activated, they will animate when the door opens or closes).
  
  Having a dedicated control setup for first-generation control logic would solve a lot of problems.
  
  
• Set/up needs to become a separately-defined notch, like "neutral" on the throttle. MSTS and OR use a flawed logic for set/up mode where you move the lever into the set/up position and then a timer prevents further motion. This is completely inaccurate. This is based on the assumption that the operator must wait for some time while the handle is in set/up prior to moving the handle into the braking range. This is backwards. In reality, the operator is "strongly encouraged" to wait 10 seconds after retarding the throttle to idle before placing the handle in set/up:
  
  

  Quote

  CAUTION: During transfer from power operation to dynamic braking, the throttle must be held in IDLE for 10 seconds before moving the dynamic brake handle to the SET UP position. This is to eliminate the possibility of a sudden surge of braking effort with possible train run-in or motor flashover.
  
  
  On an AAR control stand, this is clearly indicated on the placard placed above the handle itself. There is nothing preventing the operator from moving the handle whenever - it's just clearly contraindicated on both the control console and in the operator manuals. The obvious workaround would be to remove the delay timer. The problem is, if you set the timer to "0," then the lever will usually just skip the set/up notch and go directly into dynamic braking.
  
  
• On a related note - there is nothing preventing the reverser from being moved while the train is in motion in real life. Is it against protocol? Yes. Is it done? Yes.
  
  
• The furthest-forward detent on the throttle is labelled STOP. This performs an emergency stop of the engine. Using this detent requires the operator to pull the lever outward and shove the lever forward. It would be nice to see this implemented.

[Traindude]

Transitioning levers for rheostatically controlled electric/diesel-electric locomotives would be nice.

Also, if we're talking about gauges as well, here are some ideas:

For steam:

• Back Pressure Gauge: Not all locomotives have them, but if so equipped, they help the engineer in choosing the right cutoff setting. These measure the pressure of the exhaust steam from the cylinders. The extended HUD (Alt+Shift+F5) has a back pressure parameter, so theoretically the gauge can be added easily. One rule of thumb back in the day was that in freight service, 6-14 psi back pressure was considered the most efficient in terms of fuel economy.
  
• Pyrometer: Commonly used on superheated locomotives to measure the temperature of the incoming steam to the cylinders. Generally, the reading of the gauge when the throttle is open is equal to (based on the extended HUD parameters) the sum of both the Water Temperature and Current Superheat. Anything lower than that with the throttle open is an indication of priming, foaming, a bad fire condition, low fire temperature or other adverse condition. Here is an example of how it is used.
  
• Stoker Steam Gauge(s): On locomotives equipped with mechanical stokers, these allow the fireman to judge the pressure used by the stoker engine (thus determining the speed of coal feed) and at each of the stoker distributor jets (how far forward in the firebox the jets spray the coal).
  
• Firebed (For 3D Cabs): It would be nice to have the height of the firebed rise and fall with the Fire Mass value, perhaps just a flat plane that raises and lowers itself inside the firebox.

[darwins]

For around 70 years from about 1900 almost all electric multiple unit trains and trams around the world used some variation of the Sprague automatic acceleration multiple unit control system. Yet this was absent from MSTS and is so far absent from OpenRails.

On early trams and commuter trains drivers notched up manually, moving the controller one notch at a time to cut resistors out of the circuit until the motors were connected either in series or in parallel without any additional resistors in the circuit. The controller might perhaps be:

OFF
1 - first series notch with all resistors in circuit
2
3
4
5 - FULL SERIES = half power = motors in series with no resistance in circuit
6 - Set Up or first parallel notch = change in circuit connection from series to parallel with all resistors in circuit*
7
8
9
10 - FULL PARALLEL = full power = motors in parallel with no resistance in circuit

This required a certain amount of skill from the driver watching an ammeter to notch up at the right time. Automatic acceleration made this easier. The controller only needed three notches:

OFF
SHUNT - first series notch with all resistors in circuit - used for low speed in sidings etc.
FULL SERIES
FULL PARALLEL

Later controllers often had additional notches for field weakening.

To accelerate to full speed the driver simply moves the controller from OFF to FULL PARALLEL and the controller changes the notch either as the current falls to a certain level or after a certain time interval.

This much we can simulate reasonably well using ORTS tractive force curves, although a dc motor model would do this more accurately.

What we could add in to OR for acceleration with older trains would be the 'click' of the relays when changing from one notch to the next. This would need a sound trigger for automatic notching up. (I am not sure if the cab control one could be used externally for manual notching up.)

The bit that Open Rails can not do is what happens when the controller is moved backwards. Automatic acceleration controllers of this type can not "Notch Down".**

Imagine the controller is at FULL PARALLEL but the train is still notching up through the parallel notches. In most cases if the driver moves the controller back to FULL SERIES, the notching up will stop and the train will remain in whatever notch it is in either until the controller is advanced to FULL PARALLEL again or until the controller is moved to OFF.

In order to reduce power from FULL PARALLEL to FULL SERIES the driver must move the controller to OFF. This disconnects power from the motors. The controller can then be moved to FULL SERIES and the train will again 'notch up' until that notch is reached.

Whenever a manual or automatic controller is moved from a power notch to OFF then a blowout relay is used to disconnect the power. This produces a loud "pop" sound. A sound trigger would be needed for this in OR.


* There are different ways of reconnecting a series circuit to form a parallel circuit, some of this included an open circuit - which would use the blow out relay again - and some would have used reduced power by operating with only half of the motors.

** This applies only to trains using a dc supply. It does not apply to the automatic notching used to notch up and notch down through transformer taps on trains using single phase ac supply.

[Weter]

Quote

This would need a sound trigger for automatic notching up

Not a problem, Darwin!
As long as Variable2 for electric traction is Load's value, what if to use triggers as Variable2 increases over X / Variable2 decrease over X?

Quote

There are different ways of reconnecting a series circuit to form a parallel circuit

There is a "bridge" scheme, where power isn't being interrupted completely.
BTW, for economy reasons, often the same MRC's positions are used for DB notching, with different motor connection by standalone brake mode selector(s)

The problem is that eccentric shaft of MainRheostaticController rotates only forward.
To step in previous notch, it has to make full turn, through zero notch, then continue towards desired notch further.
When power contactors are controlled individually, but not by common shaft, any notch is accessible at any time.

Quote

if the driver moves the controller back to FULL SERIES, the notching up will stop and the train will remain in whatever notch it is in

Either tranzition scheme will be disassembled, so there could be series connection recovered, but with significant jerk, caused by current jump. This is prohibited way of operation.

Quote

(I am not sure if the cab control one could be used externally for manual notching up.)

Please, explain, what did You mean?

[darwins]

Some early electric trains did not use the bridge system to change from series to parallel connection. Here is one example:

1898 – Waterloo and City Railway

500 v direct current from centre conductor rail.
4 car trains formed of two motor cars and two trailers. Motor car has 2x Siemens 60 hp motors.
Brakes Westinghouse – no compressor. Reservoirs charged to 100 psi at Waterloo station.
Siemens controller with manual notching. (Direct control).

0 – OFF

1 – all resistance in circuit with 4 motors in series

2 – ½ resistance in circuit with 4 motors in series

3 – SERIES

T1 ½ resistance with 2 motors in series and 2 motors short circuited

T2 ½ resistance with 2 motors in series and 2 motors disconnected

4 – ½ resistance with 2 motors in series in parallel with 2 motors in series

5 – ¼ resistance with 2 motors in series in parallel with 2 motors in series

6 – SERIES-PARALLEL

T3 ¼ resistance with 2 motors in parallel and 2 motors short circuited

7 – ¼ resistance in circuit with 4 motors in parallel

8 – PARALLEL

I have attached a summary of electric multiple unit history in UK. I expect similar changes were seen around the world.



On older units, "notching up" was carried out by large electromagnetic relays, often in a compartment behind the driver. So during acceleration you can hear the clicks of the switches for example in this video leaving the station at 6m15s to 6m25s.

With manual control you would hear the switches click when the driver moved the throttle each notch.

Attached File(s)

•  Electric Multiple Units History.pdf (63.99K)
  Number of downloads: 164

[Weter]

I've just forgotten to say: some of EMUs had "antislip" button, which actually worked as Hi/low acceleration toggle (mentioned in MSTS docs, but caused game to crash, if engaged). So, in bad rails condition (wet, greased, etc.) driver could press that button (sand bunkers took place too, but EMUs could have to use them too often), which forced notching-up to occur at greater current drops, than during normal mode, so acceleration were slower)
Also, there were two special notches for manually noticing-up in case of control system's malfunction.
As it was said, driver's controller handle (not telling about dynamic brake range, if it was present) had:
0 (off)
M (maneuver, i.e. slow movement)
I series
II series weak field
IIA manual notching A
IIIA manual notching B
III parallel
IV parallel with wakened field

This post has been edited by Weter: 24 September 2022 - 11:52 AM

[darwins]

 Weter, on 24 September 2022 - 02:46 AM, said:

I've just forgotten to say: some of EMUs had "antislip" button, which actually worked as Hi/low acceleration toggle (mentioned in MSTS docs, but caused game to crash, if engaged). So, in bad rails condition (wet, greased, etc.) driver could press that button (sand bunkers took place too, but EMUs could have to use them too often), which forced notching-up to occur at greater current drops, than during normal mode, so acceleration were slower)

That is interesting. London Underground trains had a similar "rate switch" to accelerate more slowly. This was not in the same place as the main controller handle so it would only be changed when the train was standing.

https://i.imgur.com/VZWZ6q6.jpg

We will have to be careful about names used, as in UK an "antislip" button is a kind of brake found on older diesel and electric locomotives. The driver presses the button to get 5 or 10 psi ( 0.3 or 0.6 bar ) in the locomotive brake cylinders to reduce any wheelspin. This is also not yet in OR.

Quote

Also, there were two special notches for manually noticing-up in case of control system's malfunction.
As it was said, driver's controller handle (not telling about dynamic brake range, if it was present) had:
0 (off)
M (maneuver, I.e. slow movement)
I series
II parallel
IIIA emergency notching A
IIIБ emergency notching B
IV parallel with wakened flux

Could you explain what happens in IIIA and IIIБ?

[Weter]

1. Exactly as You've said: that pushbutton, while pressed, lowers measured power cirquit current's threshold, (which causes acceleration/deceleration relays* to issue command for "notch 1 step up" every next time), to less value, therefore automatic notching-up becomes slower. (*these relays work either for traction or electrodynamic braking, detecting current values, when main rheostatic controller's shaft have to turn one step forward).
2. In quoted text might be a misspelling: "London Transport....relays to switch and at(?) either higher or lower current"
3. You really told about such special IB application buttons. I've just forgotten. I said "antislip" as it was used in *.eng-files
4. Roughly speaking, if failed control circuits are shut down by "manual notchingl" button, then normal notches (I,II,III,IV) do nothing (they normally indicate, where GRK (main rheostatic controller's) shaft, controlled by RUTs (acceleration/braking relays), had to stop: series, parallel, full wakened flux main notches), but M, IIA and IIIA will allow manual control of GRK, issuing notch-up 1/2 commands. So failed EMU train could finish its ride and return to depot by itself. For more exact description, I need to see books.
If malfunction occur in particular motor car, it's possible to switch it's circuits off the train's scheme and operate without it (it became a trailing car then)

This post has been edited by Weter: 24 September 2022 - 11:55 AM