[Weter]

Another question: is it possible to model in ORTS, using features, that we already have, the 394&395Э trainbrake controller's behavior?
https://техучеба.рф/wp-content/uploads/2017/10/Кран-машиниста-395.jpg
Note the sector in the next picture to see, wich position is notched, wich-no.
http://rcit.su/gif/tiM0-10.gif
First, at I handle position, the BP is connected to the MR directly, so its recharging goes rather fast and BP gains high pressure.
As a result-fast recharging of long freight trains and guaranteed release of triple valves in each wagon (as some of them may be hardly released)

Second, at II handle position, feeding of the BP is made through the reductor, which releases excessive air till the pre-setted by the engineer pressure is achived, then, as leakage from BP continues, the reductor compensates that losses (is it equal to "Running" state?)
It's possible to perform "normal" brake release by II position, BUT MSTS (ORTS?) can't release brakes such way (or I don't know, how?)

The dream is to have special control, simulating reductor adjusting (say, +- 0,8 bar around 6), but it's not so principial, at last.

Third:
III,IV,V and VI positions can be modelled rather good (they looking much like Lap, Hold, Service and Emergency, resp.)

But there's V-A and it can mean either:
-very slow discharging of BP, for prevent stressing of couplers in case of very long freight trains (the "Soft tempo")
and I don't see, if the "MinimalReductionStart" is adequate substitute for this (again, maybe I'm not clever enough);
-or, in case of passenger modification, the V-Э is the NOTCH, where Hold status remaining, but EP signal is issued to train, so wagons apply their brakes without BP discharge.
I see, it's not possible to combine EP and Auto brakes in one consist yet (am I right?), furthermore, when I use "EP Apply", I observe a pressure drop in BP, so it's not good.

So, What and how EP(ECP) brake controller model in ORTS can do at this time?

[Weter]

There are cool illustrations of 394 and 254 valves, explaining their work.
As well, the illustration of the 483 triple valve, working with them.

Translations:
Valve 394

Spoiler

The driver's valve No. 394-000-2 consists of five units: upper (spool), middle (intermediate) and lower (equalizing) parts, a stabilizer (throttling outlet valve) and a reducer (feed valve).

Valve top part has slide valve 12, cover 11, rod 17 and handle 13 with retainer 14 fitted on rod square and secured by screw 16 and nut 15.

Rod 17 is sealed in cover by collar resting on washer 19. The lower end of the rod is put on the projection of the slide valve 12 which is pressed against the mirror by the spring 18.

To lubricate the slide valve, the cover 11 has a hole closed by a plug. Lubrication of rubbing surface of rod 17 is performed through axial hole drilled in it.

The middle part 10 of the valve serves as a mirror for the slide valve, and the bushing 33 pressed into it serves as a seat for the check valve 34.

Lower part of driver's valve consists of housing 2, equalizing piston 7 with rubber collar 8 and brass ring 9 and outlet valve 5, which is pressed by spring 4 against seat of bushing 6. Outlet valve shank is sealed by rubber collar 3 inserted into base 1.

The upper, middle and lower parts are connected through rubber gaskets on four studs 20 with nuts. Position of cover flange of upper part is fixed on middle part by pin 21.

The valve's reducer has an upper portion housing 26 with a press-fit sleeve 25 and a lower portion housing 29. At the top is a feed valve 24 pressed against the seat by a spring 23 which at its second end abuts against the plug.

The filter 22 protects the feed valve from contamination.

A spring 30 is pressed against the metal diaphragm 27 from below through the thrust washer 28, which is supported by the second end through a stop 32 on the screw 31.

The driver's valve is connected to the pipes from the feed and braking lines using swivel nuts.

Valve's stabilizer consists of housing 7 with bushing 4 pressed into it, cover 1 and valve 3 pressed to seat by spring 2. Nipple 5 with calibrated hole of 0.45 mm is also pressed into the housing. Metal diaphragm 6 is clamped between housing and bushing 9. Spring 10 presses on diaphragm from below through washer 8, compression of which is adjusted by screw 11.

The valve's handle has 7 positions:
Position I - charging and Release.
Air from feed line A is supplied through channels ГР, 4, 5 and M to brake line and simultaneously through hole 13, recess УР1 and hole УР2 - to camera above equalizing piston, and from there through calibrated hole Г with diameter of 1.6 mm, through channel B - to equalizing reservoir УР. Pressure increases faster in camera above equalizing piston than in brake line. Piston descends, pushes outlet valve from seat and communicates channel A1 with main line.

At the same time, air from the feed line is supplied to the reducer valve via channels ГР, 3, Р2 and Р3.

Camera above equalizing piston communicates through hole УР4, recess 8 and hole C with stabilizer and further with atmosphere.

<<At the I position of the valve's handle, you can use the pressure gauge of the equalizing reservoir to select the amount of pressure that will be set in the brake line after the valve's handle is moved to the II position.>>

Position II - Running.
Air from feed line A flows through ГР channel, through recesses 2 and Р2, hole Р3 and open valve of reducer into camera above equalizing piston and into equalizing reservoir УР. The reducer automatically maintains steady pressure in the equalization reservoire.
<<The driver can adjust this pressure changing the reducer's spring tension by rotating the nut at the bottom of reducer>>
The supercharging is eliminated by the stabilizer.

If the pressure in the brake line is lower than in the camera above the equalizing piston, this piston will move down and communicate with each other channels A1 and M.

Camera above equalizing piston through hole УР4, recess 8, hole C and hole C2 0.45 mm diameter communicates with atmosphere at pressure in cavity C1 about 0.3 - 0.5 kgf/cm² referred by the stabilizer spring.

The air pressure in the equalizing reservoir, despite the air flow through the hole C2 of stabilizer, will be maintained by reducer.

Position III -Lap without feeding of the brake line.
Camera above equalizing piston and equalizing reservoir communicate via check valve with brake line. The pressure in the equalizing reservoir and the brake line is equalized. At the same time, the check valve does not allow an increase in pressure in the equalizing reservoire (fixes the lap). Reducer and stabilizer are disconnected by slide valve.

Position IV - Lap with feeding of the brake line.
All holes and recesses on the mirror are blocked by a slide valve. Pressure in brake line is maintained equal to pressure in equalizing reservoire.

Position V - Service apply.
The air from the equalizing reservoir and the camera above the equalizing piston flows into the atmosphere through a recess in the slide valve and a 2.3 mm calibrated hole. The equalizing piston will move up and communicate the brake line with the atmosphere. The exhaust of air from the main line will stop when the pressures in it and the equalization reservoir are equal. In this case, the pressure drop in the brake line and the equalization tank will occur at the same rate - from 5.0 to 4.0 kgf/cm² in 4-5 seconds.

VA position - service apply in "soft rate" for the long trains.

The equalization tank is discharged in the same way as at the V position, but through the hole with a diameter of 0.75 mm at a rate from 5.0 to 4.5 kgf/cm² in 15-20 seconds.

Position VI - emergency braking.
Air from brake line and camera above equalizing piston is released into atmosphere through recess in slide valve. At that, equalizing piston moves upwards and communicates brake line with atmosphere along the second channel. In addition, the equalization tank also communicates in two ways with the atmosphere: through a channel in the slide valve and a throttle hole with a diameter of 1.6 mm and a cavity above the equalization piston.

The pressure drop in the brake line is faster than in the equalization tank at a rate from 5.0 to 1.0 kgf/cm² in 3 seconds.

<< there can be the "round cap-like" block above the valve's handle, containing electric micro-switchers.
In freight modification 394, the purpose of it is turning on the sanders if the handle is at Emergency position and cut-off power to traction motors.
In passenger modification 395, the other switchers are commutating EP brake circuits at VA position to order applycation of EP brake of coaches, wile the pneumatic part remains at Hold state, so BP is feed with air by MR and supplies ARs of the coaches and their BCs with compressed air, because the system is single-piped.>>

Air distributor 483

Spoiler

The set of air distributor No. 483-000 includes:
Line part No. 483-010
Main part No. 270-023
and two-chamber reservoir No. 295-001.

Construction
Two-chamber reservoir No. 295-001 has 6 liter working chamber PK in the cavity of housing 1 and 4.5 liter slide valve's chamber ЗК. The main part of the air distributor is attached to the sealing flange 2, and the line part is attached to the flange 9.

Filter 8 secured by cover 6 prevents air distributor from clogging.

On the mode roller (7) with eccentric the handles (4) are fixed with cotter pins, which are brought to the outer side beams of the car frame, where there are planks with designation of modes (П - empty, C - middle, Г - loaded).

Pin 3 pressed into end of mode roller is fixed by spring 5 in one of three recesses on body boss. To switch to the required mode, it is necessary to squeeze the roller before the pin leaves the recess.

Nozzles 10 equipped with mesh caps 11 and rubber rings are screwed into the tank body. Pipes diameter of Xx" from brake pipe M, the ЗР auxiliary reservoir and a brake cylinder of ТЦ fasten to unions cap nuts 12.

Main part No. 270-023. Brass bushing 7 and seat 14 of check valve 11 are pressed into housing 1 of main part.

A valve having a rubber seal 13 and a spring 12 is closed by a threaded plug 10.

Main piston 2 is sealed with two rubber cuffs 5, and for lubrication of working surface of housing is equipped with felt ring 4 with flat spacer spring 5. In an experimental batch of air distributors, main pistons with one collar and two felt rings are installed.

One end of spring 6 rests against housing recess and the other end rests against main piston. The initial tension of this spring (about 20 kgf) provides forced movement of the piston to the extreme left position during release.

Hollow rod 8 with six rubber cuffs 9 separating different channels and cavities in housing of main part is screwed into main piston. The seat 27 of the valve 29, which is supported by the spring 30 and has a rubber seal 28, is screwed inside the stem. Hollow rod with cuffs and valve plays the role of slide valve.

In the right part of the housing there is an equalizing piston 16 with a rubber collar 26 and a felt lubricating ring 25 spread by a flat spring 24. Left end of equalizer piston is guided by bushing 7, right end - by cylindrical surface of housing. The equalizing piston has a valve seat 29. An atmospheric hole with a diameter of 2.8 mm is drilled in the saddle.

The equalizing piston is pressed with two mode springs: large 17 and small 18. The first is adjusted by a stop 20, the second by a stop 21 provided with a screw 22. Thrust of big spring is fixed by screw 19, which enters one of its cuts.

The small spring abutment screw 22 is secured by a cotter pin 23 which extends through the hole in the screw and into respective slots at the end of the threaded portion of the abutment 21.

In the empty mode, when the eccentric of the mode roller located inside the double-chamber reservoir is in the extreme right position, the head of the screw 22 does not reach the eccentric and the small spring 18 is turned off, that is, it does not act on the equalizing piston.

In the loaded mode, the eccentric is in the left extreme position, the screw 22 abuts against it and turns on the small spring. In the middle mode, this spring is turned on only part of the full force.

The cover 40 houses a release valve consisting of a seat 32, a guide 31, a rubber seal 36, a valve 37, and a spring 38.

The rod 34 to which the lead chain is attached is pressed against the seat 35 by the spring 33.

The cover is attached to the main body via a gasket 41 by four nut bolts 39. A seal is placed on two bolts. To control the charging time of the spare tank, a nipple 42 with a throttle hole with a diameter of 1.3 mm is pressed into the main body main channel.

Gasket 15 seals the connection of the main part of the air distributor to the sealing flange of the double-chamber reservoir.

Line part No. 483-010 consists of housing 1 and cover 6, inside which there are three assembled units: diaphragm 7 with plunger 11, fixed between disks 5 and 8; seat 10 with collar 25 and bushing 24 secured by ring 26; assembly of three seats 30, 31 and 33 with spring-loaded valves 32 for additional discharge of main line and 34 for discharge of slide chamber.

Collar (3) with spacer bushing (2) simultaneously serves as seal of disk (5) shank, and its end part is valve, which, when resting against seat (30), disconnects chambers MK (holes (28)) and ЗK. Nipple 27 with 2 mm diameter hole is pressed into plunger 11. In the plug 35 there is an opening with a diameter of 0.55 mm for discharging the ЗК chamber into the atmospheric channel A.

Flat/mountain mode device consists of rubber diaphragm 12, plastic cap 13 of springs 21 and 22, stop 20 with screw slot and felt lubricating ring 19 and handle 18 for switching.

Letters Г and P corresponding to position of mountain and plain modes are cast on cover (6). The abutment 20 moves axially by 11 mm. A sleeve 42 is pressed laterally into the housing 1, in which is disposed a softness valve consisting of a housing 41, a diaphragm 39, a spring 37 and a plug 36. Diaphragm 39 is secured between rings 38 and 40.

On both sides of diaphragm (7) there are two chambers: main MK and slide valve ЗК, and on the left side of diaphragm (12) there is a cavity (23) connected in plain mode with working chamber. At mountain mode cavity 23 is isolated from working chamber. Chamber of КДР behind valve 32 of additional discharge of main line by special channel in housing 1 is connected with main part of air distributor.

The line part No. 483-010 in the aluminum version has a mass of 5.6 kg instead of 12.5 kg in cast iron. At the place of welding, the main part is interchangeable with the main parts of air distributors No. 270-002 and 270-005-1.

Action
Charging. Air from brake pipe is supplied to MK and moves diaphragm (7) with plunger (10) until disc (8) rests against end of seat (22). Through two holes 27 with diameter of 1 mm, central hole 11 and hole 12 and 13 and plunger air is supplied to cavity K and through holes 15 and 14 to ЗK.

Working chamber is charged in flat mode to pressure 0.2-0.35 MPa through hole with diameter 0.5 mm in main part, and then in second way through hole 21 with diameter 0.6 mm in seat 22, and in mountain mode - only through hole with diameter 0.5 mm in main part. When the air pressure in the ЗК is about 0.4 MPa, the valve 36 moves upward and opens the second charging path of this chamber from the manifold through the throttle 40 and the opening 39 in the seat 38. The charging time to the pressure of 0.12 MPa of the spool chamber occurs in 20-35 s and the working chamber in 65-95 s. The pressures at which the second recharging paths of the spool and working chambers open are indicated optionally and fluctuate within large limits.

The auxiliary reservoir (ЗР) is charged directly from the main via a 1.3 mm diameter opening 41, a check valve 45 and a channel 42. After alignment of pressure in ЗK and MK the diaphragm 7 under a spring force 9 moves to the left against the stop pushers 24 to valve 29. Note here that plunger holes 12, 13 and 15 extend beyond cuff 23 while holes 27 extend beyond cuff 26. Chambers MK, and ЗK remain connected only through hole 40 with diameter of 0.65 mm (train position).

Brake chamber communicates with brake cylinder and through hole 47 in seat of equalizing piston - with atmosphere A.

The distance from the end of the seat 4 to the end of the disc 5 in the extreme right position of the disc, that is, the full travel of the diaphragm, is 11 mm. After complete discharge in the train position, the distance from the end of the seat 4 to the end of the disc 5 is about 4.5 mm.

Discharge (softness). Such discharge is carried out in two ways. When the pressure in the main line decreases at a rate of up to 0.02 MPa per 50 s, the air flows from the charging chamber and the combustion chamber into the main line through the hole 40 without causing movement of the diaphragm 7.

At faster decrease of pressure in the main line with rate of up to 0.1 MPa per 1 min, diaphragm 7 will start to move to the left, valve 29 opens and discharge of ЗК in КДР takes place at a rate equal to the rate of discharge of the main line, at that cuff 26 is not pressed from seat 4.

Braking. In case of pressure decrease in the main line by service braking rate (0.006 - 0.04 MPa per 1 s by value not less than 0.03 - 0.04 MPa) or emergency (more than 0.08 MPa per 1 s) diaphragm 7 moves from the position of shutoff to the left by 1.5 mm, opening valve 29 completely. There is a sharp pressure drop in the cavity between the valve 29 and the cuff 26, as a result of which the cuff 26 moves away from the seat 4, communicating the MK through six holes 25 with a diameter of 2 mm with the atmosphere A and the brake cylinder. At the same time air from КДР enters the cavity above diaphragm 35 and valve 36 shuts off MK and ЗК communication through holes 39 and 40.

With the disc 5 moving further to the left by another 1.5 mm, the valve shank 29 pushes the valve 30 away from the seat 2 by 1 mm, communicating the КДР through an opening 32 with a diameter of 0.55 mm or 0.9 mm in the cap 31 with the atmospheric channel Ат. Further movement of disc (5) until stop against the end face of seat (4) will cause opening of valve of plunger (10) by 1.5 mm, and quick discharge of ЗК to КДР will occur.

The discharge of M and ЗК in КДР stops the first cuff on a rod of the main piston of the air distributor, pressure on both sides of a cuff 26 are leveled, and a spring force she sits down on a saddle 4. At the initial moment discharge of the valve in the air bypass valve provides reliable actuation for braking of the main part and generation of surge pressure in the brake cylinder. When diaphragm 7 is in the leftmost position, further discharge of ЗК continues to atmosphere through open valve of plunger 10, valves 29, 30 and hole 32.

The brake cylinders are filled with compressed air in the head part of the train (or on a separate car) at a hole 32 with a diameter of 0.55 mm is almost independent of their volumes and the output of the rods, as well as from the activated mode for loading the car. Time of cylinders filling at loaded mode to pressure of 0.35 MPa in them is 14-20 s in case of emergency and 16-22 s in case of full service braking. With a hole 32 with a diameter of 0.9 mm, this time is mainly determined by a hole with a diameter of 1.7 mm in the stem of the main piston. Therefore, the cylinder filling at this hole depends to a certain extent on the above factors and occurs at the loaded mode up to a pressure of 0.35 MPa for 7-14 s during emergency and full service braking.

When the pressure in the spool chamber decreases, the main piston moves to the right, closes the hole 44 with the collar and interrupts the communication between the ЗК and РК.

Simultaneously, the brake valve closes the opening 47 and disconnects the brake chamber and the brake cylinder from the atmosphere A, and then communicates the spare reservoir with the brake cylinder.

In the tail part of long-train trains, the pressure in the main line decreases slowly during braking, and the ЗК continues to discharge into the atmosphere. The diaphragm 7 therefore begins to move to the right, closing the valve of the plunger 10. The ЗК is then discharged only through the throttling holes 12 and 13 and further to the КДР, and the latter, having a small volume, is discharged to the atmosphere. The pressure of the КДР drops 0.15 to 0.20 MPa lower than in the main line (this value is determined by the force of the spring and the area of ​ ​ the valve 26), the valve (cuff) 26 leaves the seat and communicates the main line with this channel and further with the atmosphere through the open valve 30 and hole 32.

Opening of valves 26 in the air distributors of the tail part of the train occurs periodically during the entire braking process, thereby accelerating the discharge of the main and, accordingly, filling the brake cylinders in the train of 100 cars by about 15-20% with a hole 32 with a diameter of 0.55 mm and 30-40% with a hole with a diameter of 0.9 mm compared to air distributors No. 270-005-1.

After service braking of pressure in M and ЗК, valve 30 and diaphragm 7 are shifted to the right under spring force. Valve (30) closes and stops the discharge of air bypass valve to atmosphere At. In this position, called shut-off, the КДР remains in communication with the ЗК through the open valve 29.

There is no possibility of blowing in these devices, since the ЗК is discharged separately from the main line by directly entering the atmosphere At, which helps to quickly set the diaphragm to the shut-off position.

If when the diaphragm is in the shut-off position there will be overpressure in the line by 0.01 - 0.025 MPa, the diaphragm with plunger will move to the right and РК will be connected to the ЗК. through holes 15 and 14. The pressure in the valve will increase slightly, and the diaphragm with the plunger under the force of the spring 9 will move to the left until the pusher 24 stops against the valve 29, the discharge of the valve will stop. This ensures stability of the overlap position after service braking.

Release in plain mode. In the head part of the train, the diaphragm moves to the right until the end face of the disc 8 abuts against the end face of the seat 22. Air from the main line through holes 27, 11, 12 and 13 from РК through hole 21 will flow into cavity K and further through holes 15 and 14 to ЗК.

In the tail part of the train, with a slow continuous increase in pressure in the main line at a rate of more than 0.01 MPa per 5-7 s, the diaphragm with the plunger takes such a position at which the РК first communicates with the ЗК through holes 15 and 14, and with a further increase in pressure in chamber M, communication with it of the working chamber opens through holes 12 and 27.

In case of slower increase of pressure in the main line, tempering occurs due to equalization of pressures in РК and ЗК through holes 15 and 14. Complete tempering in this case will occur when the pressure in the line increases by an amount of about 40% of the pressure decrease during the previous braking.

The section of the holes and their location in the plunger 10 are selected in this way, that in the head part of the train, when using the I position of the driver's crane handle, the vacation begins earlier, but flows slowly due to maintaining high pressure in РК, and in the tail part it starts later, but flows faster due to the flow of air from the working chamber into the spool chamber and the main line, which ensures the equalization of the release time along the length of the train. Note here that in mid-length compositions, tail car brakes release in flat mode takes place earlier than head ones to ensure appropriate smoothness of train during brake release.

After complete release, air bypass valve communicates with atmosphere A through the main part. Under the pressure of air in the ЗК, the valve 36 opens and communicates the main line with this chamber with the holes 39 and 40. In a train of 100 cars, the brake release time after the braking stage does not exceed 50-60 s.

Mountain mode release. In the Г position of the mode stop, diaphragm 20 remains pressed against seat 22 by the force of two springs. Therefore, during release, the working chamber does not communicate with the main and spool chambers, and the release occurs only by increasing the air pressure in the spool chamber supplied from the brake line through the holes 27, 11, 12, 13, 15 and 14.

Air distributor No. 483-000 has the following properties: a high brake wave propagation speed (290-300 m/s) and an improved diagram of the filling of brake cylinders in the train, which reduces longitudinal forces during braking and allows you to drive trains weighing 80-100 thousand kN.

[darwins]

Hello
The answer is no it can not be done in OR at the moment.
The answer applies not just to those specific controllers, but to very many air brake controllers old and new.

Two things that will need to change in the model to allow this:
1. Overcharging needs to be allowed. At present the system can never exceed the value of TrainBrakesControllerMaxSystemPressure - so an overcharge value would need to be added. Then as you say we would need to ensure that the reservoir pipe was gradually returned to normal working pressure when the brake handle is returned to the "RUNNING" position.

2. For twin pipe systems different values need to be allowed for the main reservoir pressure and the reservoir pipe pressure - at present both are determined by AirBrakesMainMaxAirPressure
Another note is that OR brake token names do not correspond to the common positions on many brake handles.
In OR TrainBrakesControllerRunningStart has only the effect of a HOLD or LAP position - it does not restore the brake pipe to normal pressure after a reduction.

In general I have used TrainBrakesControllerFullQuickReleaseStart for the RELEASE position on brake controllers (although it does not do overcharge) and TrainBrakesControllerReleaseStart for the RUNNING position as it will maintain train pipe against leakage and slowly return TP to normal pressure after a reduction.

Three main types of controllers used for air brakes in UK were as follows.
1. For older electric trains and steam trains using Westinghouse brakes - air single pipe system

  	Brake_Train ( 0 1 0.01 0.50
      	NumNotches ( 5
         	Notch( 0.0 0 TrainBrakesControllerFullQuickReleaseStart ) Comment ( RELEASE - connects brake pipe to main reservoir )
         	Notch( 0.25 0 TrainBrakesControllerReleaseStart ) Comment ( RUNNING )
         	Notch( 0.50 0 TrainBrakesControllerHoldStart ) Comment ( LAP )
         	Notch( 0.75 0 TrainBrakesControllerFullServiceStart ) Comment ( APPLY )
         	Notch( 1.0 0 TrainBrakesControllerEmergencyStart ) ) )

These did not have graduated release - so it would be good if this could be put in the eng file rather than on the options tab.
2. As used here on diesel and electric locos in 1960s and 1970s with twin pipe system (with graduated release!)

Brake_Train ( 0 1 0.1 0.2
 NumNotches ( 4
  Notch ( 0.0  0 TrainBrakesControllerFullQuickReleaseStart ) Comment ( RELEASE - sprung position - overcharges train pipe )
  Notch ( 0.1  0 TrainBrakesControllerReleaseStart ) Comment ( RUNNING )
  Notch ( 0.2  1 TrainBrakesControllerContinuousServiceStart )
  Notch ( 1.0  0 TrainBrakesControllerEmergencyStart )))

Comment ( add ANTI SLIP brake )

Brake_Engine ( 0 1 0.1 0.0
 NumNotches( 1
  Notch( 0 1 EngineBrakesControllerContinuousServiceStart ) ) )

3. A modern stepped brake

Brake_Train ( 0 1.0 0.01 0.2
NumNotches ( 9
Notch ( 0	0 TrainBrakesControllerFullQuickReleaseStart ) Comment ( RELEASE )
Notch ( 0.01 0 TrainBrakesControllerReleaseStart ) Comment ( RUNNING )
Notch ( 0.02 0 TrainBrakesControllerEPApplyStart )
Notch ( 0.16 0 TrainBrakesControllerEPApplyStart )
Notch ( 0.40 0 TrainBrakesControllerEPApplyStart )
Notch ( 0.65 0 TrainBrakesControllerEPApplyStart )
Notch ( 0.80 0 TrainBrakesControllerEPApplyStart )
Notch ( 0.99 0 TrainBrakesControllerEPApplyStart )
Notch ( 1.00 0 TrainBrakesControllerEmergencyStart )))

Comment ( RELEASE has separate overcharge button )
 
Brake_Engine ( 0 1 0.3 0
NumNotches ( 3
Notch ( 0	0 EngineBrakesControllerReleaseStart )
Notch ( 0.3  0 EngineBrakesControllerHoldStart )
Notch ( 0.6  0 EngineBrakesControllerFullServiceStart )))

Although the brake token says 'EP' this will also give you a regular air brake with steps.

[Weter]

Thanks for joining the discussion: it seemed to me, that I'm alone here, who is interested in making air brakes more prototypic.
The first question, wich I want to ask you is why do you calling the brake pipe as

Quote

the reservoir pipe

?
I was confused a little and at first time, I thought, you was mistaken, but it was repeated further.
I suppose, there are 3 pipes:
- the brake pipe(wich causes automatic brake application in case of pressure drop in it) marked RED;
- the feeding, or the MAIN RESERVOIRE ( as it called at *.eng-file's statements) pipe, marked BLUE;
- and sometimes, the independent brakes pipe, wich connects MUed locos to synchronize their loco brake applications marked YELLOW

[darwins]

A single pipe air brake system usually has only the train pipe running the length of the trainhttp://www.railway-technical.com/_Media/whse-brake-block-v1_med_hr_med.png
Older electric multiple units with Westinghouse also had a second pipe running the length of the train. The second pipe connected together the reservoirs on all of the motor coaches. This was not a "reservoir" pipe in the sense of the two pipe system, I was really just a way to make a larger air reservoir by joining together all the main reservoirs to create one large reservoir. The brake system on these electric multiple units was still a single pipe system like the one in the diagram as the auxiliary reservoirs are charged from the train pipe.
A twin pipe air brake system has both a main pipe and a reservoir pipe running the length of the train:http://www.railway-technical.com/_Media/two-pipe-air-brake-pic_med.png
This provides for a faster release of the brakes by charging the auxiliary reservoirs from the "reservoir pipe" rather than from the train pipe. (Twin pipe vacuum brakes work in a similar way.)


Until recently EP brakes worked in a similar way to twin pipe air brakes as they had both a reservoir pipe and a train pipe running the length of the train. In addition they had electric cables that could then provide for both fast release and fast application.http://www.railway-technical.com/_Media/whse-ep-brake-elec-pic_med.png

More modern EP brakes have replaced the train pipe with an electric cable so that now the reservoir pipe provides for all the air requirements.
http://www.railway-technical.com/_Media/brake-system-architecture_m_med.png
The diagrams are from the Railway Technical website which has more detail on different types of train brakes.

In UK at present locomotive hauled passenger trains, "freightliner" trains and most "high speed trains" use a twin pipe air brake system; freight trains use a single pipe air brake system and most multiple unit trains have EP brakes.
As a bit of history the USSR at one time developed a twin pipe system for freight trains.

[darwins]

Colour coding can be a bit confusing.
In the above diagrams - train pipe is red and reservoir pipe is blue - but on real trains the angle cocks and hose connections are red for train pipe and yellow for reservoir pipe.
The MU air connections between locomotives generally seem to have white connectors and angle cocks.

[Weter]

Oh, i see now, that you mean exactly the RESERVOIRE PIPE, as long as you mentioned a twin-pipe system (I thought, single-pipe)
Lets see the shunter's pneumatic brake diagram:
https://myswitcher.ru/tomt/tomt_1.html
And a freight car's system-single piped:
https://myswitcher.ru/tomt/tomt_6.html

Quote

Overcharging needs to be allowed. At present the system can never exceed the value of TrainBrakesControllerMaxSystemPressure - so an overcharge value would need to be added. Then as you say we would need to ensure that the reservoir pipe was gradually returned to normal working pressure when the brake handle is returned to the "RUNNING" position.

So what if we raise the SYSTEM MAXIMAL PRESSURE's value to, say 7 or 8 kgf/cm² and let it never be exceeded as is, but then we will see the missing of the NOMINAL BRAKE SYSTEM PRESSURE statement, wich is 5,1-6,8kgf/cm² usually.
And, I repeat, this last value is adjustable IRL for tune-up the brake system capabilities according to the particular operation mode(freight, passenger, flat terrain or hilly)

Also, the RESERVOIR PIPE pressure is equalized with main reservoirs and never be lower-that is its NORMAL working pressure.
This way, the given thesis is true in case of single-piped system:

Quote

For twin pipe systems different values need to be allowed for the main reservoir pressure and the reservoir pipe pressure - at present both are determined by AirBrakesMainMaxAirPressure

Quote

In OR TrainBrakesControllerRunningStart has only the effect of a HOLD or LAP position - it does not restore the brake pipe to normal pressure after a reduction.

I agree, but I think, that was from MSTS...
So why do ORTS maintain this incorrect behavior at RUNNING position?

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In general I have used TrainBrakesControllerFullQuickReleaseStart for the RELEASE position on brake controllers (although it does not do overcharge) and TrainBrakesControllerReleaseStart for the RUNNING position as it will maintain train pipe against leakage and slowly return TP to normal pressure after a reduction.

So do I. But can you say, are there adjustable values for quick and normal release rates?

Please, clear for me:
1.What distinction is between "Full Service" and "Continious Service" in ORTS?
2. Is it right , that "EP Apply" notes the handle's position value (digits) similar as "dummy" does?
I had assigned "EP Apply" at 0,4 of the handle's way and it applies about half of max pressure to BC
I tried to model VA position (see 1st post) and pasted EPApplyStart at 0,4 of handle's full span, so...

[Weter]

The typical EMU's pneumatic system diagram:
Single pipe brake system with a main reservoir pipe. It connects all Main reservoirs and supplies OTHER pneumatic equipment (doors, sanders etc.) with air.
EP mode is default, but the Brake Cylinders is filled by the BrakePipe directly, wich is feed as at Hold position.
http://scbist.com/scb/uploaded/1_1386393089.jpg

[darwins]

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So do I. But can you say, are there adjustable values for quick and normal release rates?

TrainBrakesControllerMaxQuickReleaseRate
and
TrainBrakesControllerMaxReleaseRate
should allow for different values.

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What distinction is between "Full Service" and "Continious Service" in ORTS?

Full Service - is for older non-self lapping brakes - the brake pipe pressure will continue to drop if the handle is left in this position - to hold an application you must move back to the hold or lap position.
This type of controller needs to have both TrainBrakesControllerHoldStart and TrainBrakesControllerFullServiceStart
Continuous Service is for more modern self lapping brakes - move the handle to any position between 'Running' and 'Full Service' and the brakes will gave a proportionate application - no lap or hold position needed.

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2. Is it right , that "EP Apply" notes the handle's position value (digits) similar as "dummy" does?
I had assigned "EP Apply" at 0,4 of the handle's way and it applies about half of max pressure to BC.

It is not exactly the same as dummy. The EP brake handle positions depend on the values used for TrainBrakesControllerFullServicePressureDrop and TrainBrakesControllerMinPressureReduction. You may need to adjust those to get the steps you need.
So in my example if I use

	TrainBrakesControllerFullServicePressureDrop( 24 )
	TrainBrakesControllerMinPressureReduction( 6 )

Then I should get the following brake pipe pressures -

Brake_Train ( 0 1.0 0.01 0.2
NumNotches ( 9
Notch ( 0	0 TrainBrakesControllerFullQuickReleaseStart ) Comment ( RELS = Overcharges ATP to 5.40 bar )
Notch ( 0.01 0 TrainBrakesControllerReleaseStart ) Comment ( RUN = 5.00 bar )
Notch ( 0.02 0 TrainBrakesControllerEPApplyStart ) Comment ( INIL 1 = 4.60 bar )
Notch ( 0.16 0 TrainBrakesControllerEPApplyStart ) Comment ( 2 = 4.35 bar )
Notch ( 0.40 0 TrainBrakesControllerEPApplyStart ) Comment ( 3 = 4.10 bar )
Notch ( 0.65 0 TrainBrakesControllerEPApplyStart ) Comment ( 4 = 3.85 bar )
Notch ( 0.80 0 TrainBrakesControllerEPApplyStart ) Comment ( 5 = 3.60 bar )
Notch ( 0.99 0 TrainBrakesControllerEPApplyStart ) Comment ( FULL SERV 6 = 3.35 bar )
Notch ( 1.00 0 TrainBrakesControllerEmergencyStart ) Comment ( EMGCY )))

It works near enough for everything except the 5.40 bar!

[darwins]

At the start you asked about

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The dream is to have special control, simulating reductor adjusting (say, +- 0,8 bar around 6)

This should be possible depending on the values you choose for TrainBrakesControllerMinPressureReduction and Notch ( x 0 TrainBrakesControllerEPApplyStart )

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when I use "EP Apply", I observe a pressure drop in BP, so it's not good.

Good point. For a train that has an EP system the train pipe pressure should not drop in normal operation.


This should not depend on the EPApply token though. That brake token can be used for single pipe and twin pipe air brakes to give a notched brake.

What we should have is something like this -
For BrakesTrainBrakeType( "Air_twin_pipe" ) or BrakesTrainBrakeType( "Air_single_pipe" ) the train pipe pressure should drop.
For BrakesTrainBrakeType( "EP" ) there should be no drop in train pipe pressure when the brake is applied. (This applies to both old type with a real train pipe and the modern version with a virtual train pipe.)

(I do not know how ECP brakes work either in real life or in OR - as far as I know they, like emergency reservoirs, are something found on North American freight trains.)

I have made three types of EP brake controller. This is a very early EP controller from the 1920s:

Brake_Train ( 0 1 0.05 0.1
NumNotches ( 6
Notch ( 0	0 TrainBrakesControllerReleaseStart )
Notch ( 0.1  0 TrainBrakesControllerEPHoldStart )
Notch ( 0.2  0 TrainBrakesControllerEPFullServiceStart )
Notch ( 0.7  0 TrainBrakesControllerHoldStart )
Notch ( 0.8  0 TrainBrakesControllerFullServiceStart )
Notch ( 0.9  0 TrainBrakesControllerEmergencyStart )))

The first notches are EP braking only and should not reduce the train pipe pressure - the later notches are ordinary Westinghouse air brake and should work like the older non - self lapping brakes without graduated release.

From the 1930s to the 1980s EP controllers in UK were self lapping like this

Brake_Train ( 0 1 0.05 0.15
NumNotches ( 5
Notch ( 0.0  0 TrainBrakesControllerReleaseStart )
Notch ( 0.1  1 TrainBrakesControllerEPApplyStart )
Notch ( 0.7  0 TrainBrakesControllerHoldStart )
Notch ( 0.8  0 TrainBrakesControllerFullServiceStart )
Notch ( 0.9  0 TrainBrakesControllerEmergencyStart )))

Again the first part of the controller operates the EP brake and the second part the conventional air brake. In this version the EP brake is self-lapping. As explained in this video the EP brake has graduated release but the conventional air brake does not.As before the pressure in the train pipe should not drop when the EP brake is used, but only drops when the air brake is used.

The more modern EP brakes replace the train pipe with a virtual train pipe - an electric cable - which is either ON - for all normal operation or OFF for emergency such as train divided. These are often combined with throttle and dynamic brake. They may be continuous like this one

        	Brake_Train ( 0 1 0.1 0.2
            	NumNotches ( 3
                	Notch( 0	0 TrainBrakesControllerReleaseStart )
                	Notch( 0.1  1 TrainBrakesControllerEPApplyStart )
                	Notch( 1.0  0 TrainBrakesControllerEmergencyStart ) ) )

or notched like this one

        	Brake_Train ( 0 1 0.01 0.26
            	NumNotches ( 5
                	Notch( 0	0 TrainBrakesControllerReleaseStart )
                	Notch( 0.26 0 TrainBrakesControllerEPApplyStart )
                	Notch( 0.55 0 TrainBrakesControllerEPApplyStart )
                	Notch( 0.90 0 TrainBrakesControllerEPApplyStart )
                	Notch( 1.0  0 TrainBrakesControllerEmergencyStart ) ) )

...this last one being used with TrainBrakesControllerMinPressureReduction( 1 ) in order to get the desired positions.


But yes... point well made - IRL the train pipe pressure does not fall when the EP brake is used.

[Weter]

It is interesting, thanks...

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As a bit of history the USSR at one time developed a twin pipe system for freight trains.

Have never heard about it before.

Well, I made a copy of ER2 EMU train to find experimentaly a proper tokens and settings for right EP function, but BP pressure dropped there.
The only benefits I have (what was looking like real) are fast apply (rising of BC pressure) and graduated release.
There was an artifact too: the pressure in BP jumped sometimes during returning handle to Hold position

When I will be able, I'll show you a code or send files.

You understood me a bit incorrect: when I mentioned "reductor" I meant an ability to adjust BP "normal" or, as here called "releasing state" pressure, wich then maintained at Running position (system max BP pressure - in MSTS terms) as a real 394(5) valve has a separate control, of the BP feeding device, served to adjust it for different train types (passenger 5,1; freight - till 6, and at hilly terrain-till 6,5 bar)

I experimented with brake controller of passenger diesel, as such diesels use EP IRL- I told a little bit about that... The pressure dropped too, looking like self-lapping way.

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I had assigned "EP Apply" at 0,4 of the handle's way and it applies about half of max pressure to BC.

So continues service is used after self-lapping notches and works exactly like full service, right? (constantly releasing air from BP till 0 bar) is it only different name to display in HUD?

Is separating by Hold between EP and regular ranges compulsory? (395 doesn't have special notch for it)

[darwins]

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So continues service is used after self-lapping notches and works exactly like full service, right?

No, continuous service is instead of notches it is not the same as full service.

For a brake that is not self-lapping OR Full Quick Release / Release / Hold / Full Service / Emergency = IRL Release / Running / Lap / Apply / Emergency

For a brake that is self-lapping two choices either
OR Full Quick Release / Release /Continous Service / Emergency = IRL Release / Running / Initial>>>>>>>>Full Service / Emergency
or
OR Full Quick Release / Release / EPApply / EPApply / EPApply / Emergency = IRL Release / Running / Notch 1 / Notch 2 / Notch 3 / Emergency

Sorry, my examples may be a bit confusing because the EP brake in the second one is self-lapping (and has graduated release) but the air brake is not self lapping (and does not have graduated release).
The hold is needed in that example for the air brake - if the air brake for your emu is self-lapping then you do not need hold.

Looking at your first two examples (and relying on Google translate)
The 394 controller -

I = Release = FullQuickReleaseII = Running = Release
III and IV - I am a little confused - because the system is fed or not by something being translated as "Surge Tank" ( уравнительном резервуаре ) and I am not sure if that is equivalent to the main reservoir.
It sounds as though both III and IV are variations of Lap or Hold possibly this is what the OR Running token is for and you use Running for III and Hold for IV - just a guess, not sure at all.

V = Apply = FullService
VI = Emergency

[sim-al2]

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For a train that has an EP system the train pipe pressure should not drop in normal operation.

That's not really the case though, there's implementations of EP going back quite literally to the 1890s that were merely overlaid on the existing air system, and indeed most implementations until the mid 20th century worked in parallel with the conventional valves, or alternatively were used to perform functions not easily done with a single pipe system such as holding brake cylinder pressure while charging the brake pipe.

That said, for newer implementations like "ECP" where the mechanical valves have been replaced with electronics on each car, there's no longer a need for brake pipe pressure to drop in parallel with a brake command. These systems come across as something like WABCO's various experiments with straight air like SME and SMEE where the conventional brake pipe no longer does much except for emergency functions, but suitable for longer trains.

Open Rails currently has only a basic EP implementation, with no support for the later and nothing at all for fully electric "brake-by-wire" systems like Westcode where there's no (conventional) brake pipe left, just a main reservoir pipe that serves a dual function as air supply and protection.

[darwins]

Hi Sim-al2
Thanks for the additional information.
Are you able to point me towards some sources of information about the older EP brakes that you mention? Since EP brakes were not extensively used in Europe at that time I was not even aware the existed at such an early date.
In UK the first introduction of the EP brake was the Westinghouse A type which was fitted to London Underground "Standard Stock" and District Line "F stock" in the late 1920s and early 1930s. (Some discussion here.) From the late 1930s the D type (self-lapping) EP brakes were used on all new London Transport stock. Bullied's experimental double decker trains were the first main line EMUs to have EP brakes and from 1950 onwards all new British Rail EMU stock had EP brakes. For both the A type and the D type the brake pipe pressure does not drop when the EP brake is used - only when the air brake is used.
So how to model them in OR? I understand that in general the policy is to code for the common variations of brakes and not to attempt to cater for all possible variations. On that basis there are a huge number of MSTS and OR models of trains from all around the world that have EP brakes where the brake pipe pressure should not drop. So this is definitely something that needs to be looked at.
Are there many models of trains having the older type of EP brakes that you have described? If there are not many it may be a variation to be considered in the more distant future.
There are half a dozen variations of braking systems that I would like to see included in OR - but with only one person AFAIK writing brake code at the moment then most of them are not likely to see the light of day.

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That said, for newer implementations like "ECP"...

ECP is not really a variation of EP, it is as far as I can see something totally different - although to use your words it is "overlaid on an air brake system" - there is a good description of ECP on the Railway Technical website:

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Electronically Controlled Pneumatic (ECP) brakes

A new form of electrical control of air braking is currently being tested by a number of railroads in the US. It is known as ECP and uses modern electronic techniques to overcome the problems of air braking on long freight trains.

The pure air control brake system invented by George Westinghouse in the 1860s and still used by almost all freight trains in the US and in many other parts of the world suffers from two main problems. It takes a long time for the air messages to travel along the train and there is no graduated release. For example, the delay for a reduction in train line pressure to travel from the leading locomotive to the rear of a 150 car consist can be 60 seconds. Also, you have to fully release the brake and wait for the supply reservoirs to recharge before you can reapply. Electrical control can overcome these difficulties.

ECP refers to Electronically Controlled Pneumatic brakes, key word being "Electronically" as opposed to "electrically". Older systems fitted to passenger trains (see above), use several train wires to operate individual valves or variations in switching of the wires to control brakes. Most of these systems use a second train line for main reservoir air supplies and they do not have the built-in two-way communications that ECP systems have. A car in an ECP brake train can do a self-diagnosis and report the information to the engineer and it only requires the standard train line pipe.

In summary

EP - electrically controlled - overlaid on twin pipe air brake system (modern versions replacing the the train pipe with an electrical connection) - used on passenger trains - particularly electric multiple units - used all around the world today.
ECP - electronically controlled - overlaid on single pipe air brake system - used on freight trains - particularly long freight trains - used in USA.

[Weter]

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Looking at your first two examples (and relying on Google translate)
The 394 controller -

I = Release = FullQuickReleaseII = Running = Release
III and IV - I am a little confused - because the system is fed or not by something being translated as "Surge Tank" ( уравнительном резервуаре ) and I am not sure if that is equivalent to the main reservoir.
It sounds as though both III and IV are variations of Lap or Hold possibly this is what the OR Running token is for and you use Running for III and Hold for IV - just a guess, not sure at all.

https://m.youtube.co...h?v=desAkvBhNKE
I = Charge is connection the BP to MR directly, so the pressure in BP can raise quickly and approach to MR pressure ( overcharge)
So, instead of FullQuickRelease, this causes overcharge of BP to almost MR pressure or less - depending of time, the handle was holden here before returning to Running.
This is used for quick recharging of BP during train's departure, in downhill or after coupling to a long train or for guaranteed releasing all triple in train, as some of them could freese, stick or fail to release for other reasons.
II = Running, when the pressure in BP is maintained according to the reductor setting, adjusted by the driver; if overcharged, it will decrease by stabilizer, and then the feeding of BP compensates any leaks.
The driver sets this pressure, adjusting the reductor's setting manually. This is for travelling with breakers released or for soft smooth release of brakes. Up to 3-5 minutes is need for completely release all brakes in long train this way.
III= Lap. The leaks in system are decreasing BP pressure slowly, as BP feeding stopped.
This used for test the leak rate of train before departure, the condition of break equipment and for safe breaking before terminal stations, where occasionally release of brakes may occur if use "Hold with feeding" causing collisions.
IV= Hold <that is not "surge tank", that is equalizing reservoir actually :) > so the pressure in BP is maintained to be equal to that ER pressure by feeding BP from MR. Used for test leaks from ER itself.
VA either can be
-"soft application" (freight 394 variant) when discharging performed at minimal rate, so triple walves of all train reacts only to pressure, but not to its drop rate, and this way, the application during all train lenght is more synchronous-this saves couplers of long trains of stress;
-or "EP apply" (passenger 395 variant) BUT in this case the pneumatic system remains like at IV (hold with feeding) position, but electric valves in each car connects BC to BP and AR directly, so them charged with compressed air and BP feeds AR, being supplyed by MR itself. We have single pipe system.
So it works exactly like V- the time of handle holden here determinates the BC pressure, no multiple notches or smooth range! But only one notch.
V=Full service ("full" means rate of discharge, because pressure drop depends of time, the handle was hold here by the driver)
Because the pressure drops quite fast, the triple walves in each car reacts on it and opens their own chanals to atmosphere. So BP discharges at each car and it goes faster, than during "Soft apply" this is regular braking sequence. The longer hold of handle-the higher pressure in BC.
But for driver not to concentrate on waiting for desired pressure reached in all train, he actually watches to ER manometer's needle, then returns handle to Hold and further discharge of BP automatically stops when it reaches pressure of ER.
VI= Emergency. As additional channel opened to discharge BP, the rate is 3-4 times faster, than at V.