Proper Braking Techniques

TRZ does not model all braking aspects realistically. There was an excellent article in Model Railroad a couple years back on the topic.
Dynamics are maximally effective around 30MPH (50KPH), dropping off below that and not so good above. The independent brake governs only the loco and will not stop a heavy train at any speed. Flat driving wheels are the least of the concerns. Dynamics also affect the loco(s) only so you can get some nasty effects on steep grades.
Train air is the way to go but on an extended grade you can run out of air and die. None of the simulators I've run emulate the retaining valves on the individual wagons, which are set at the top of the grade and keep the brakes partly engaged. That's a manual operation at the top and bottom of the hill.
Keep your speed low. When necessary, apply full air and stop the train, then release the brakes and let gravity take it. Hopefully your system will recharge fully before you reach danger speed again. The engineer who wrote the article recommended negotiating a downgrade at about 30MPH max.
As noted above, the dynamics on US locos shut off when train air is applied. In TRZ, not.
 
RHKluckhohn said:
Dynamics are maximally effective around 30MPH (50KPH)
Click to expand...

Typically 25 mph is max dynamic braking. They operate best from there or below. They do still function at higher speeds but their maximum braking potential is 25.

RHKluckhohn said:
As noted above, the dynamics on US locos shut off when train air is applied. In TRZ, not.
Click to expand...

That isn't correct that is why. Normally the dynamics do not shut off when the train brake is used unless it is placed in emergency but some railroads have them set to go to full dynamics when emergency application is detected. Sometimes there is also a valve present that will remove use of the train brakes on the locomotive if the dynamic brake is applied.
 
Last edited:
nysvrwx said:
I tend to try for about 20 lbs on initial, and run up the dyn brake. Then at about 20 cut that off and go to full apply.
If it's just a loco, I use ind brake until I'm going to park it.
I have been known to do the 'throw it in reverse' trick others mentioned, which I'm pretty sure would damage a real engine (anyone know?).
Click to expand...

Yep it's called "plugging" and entails reversing supply polarity (DC) or phase (AC) to the motor. I've seen a few loco manuals specifically warn against it; even for those that don't, it's generally not a good idea to do too often because plugging produces a lot of heat in short order.
 
norfolksouthern37 said:
some railroads have them set to go to full dynamics when emergency application is detected.
Click to expand...
So true, I heard the conductor of an SD70ACe on the scanner about two weeks ago laughing about his very thing. They were rolling through town and said the train went into emergency and damn near threw them through the windshield when it went into full dynamics. Probably a slight exaggeration but it was a good listen for sure.
 
RHKluckhohn said:
TRZ does not model all braking aspects realistically. There was an excellent article in Model Railroad a couple years back on the topic.
None of the simulators I've run emulate the retaining valves on the individual wagons, which are set at the top of the grade and keep the brakes partly engaged. That's a manual operation at the top and bottom of the hill.
Keep your speed low. When necessary, apply full air and stop the train, then release the brakes and let gravity take it. Hopefully your system will recharge fully before you reach danger speed again. The engineer who wrote the article recommended negotiating a downgrade at about 30MPH max.
As noted above, the dynamics on US locos shut off when train air is applied. In TRZ, not.
Click to expand...

Retaining valves (also called grade controls or "grades" or chokes) were manually applied way back when. These days however most wagons have a built in restrictive valve on the exhaust port of the brake cylinder so that the brake release is retarded giving more time to rebuild brake pipe air while the train is still effectively under braking. Would that be hard to emulate in Trainz? This does make braking empty trains on the flat quite severe at times however.

Typically dynamic will drop out if brake pipe pressure is reduced so far that the Pneumatic Control Switch drops out leaving only air brake which would already be getting pretty low. Yes, dynamic only affects the locomotives. That is why you let the train gently bunch up against the loco's at the top of the grade. Dynamic alone will not stop the train, but modern locomotives can slow it a lot before air brake is needed if at all on gentler high speed grades.

Railwayz
 
Someone really should make a script.... It would make trainz way more realistic. I thought I saw something on TPR in that order. Dynamics aren't realistic in Trainz. It is just strange that you put the dynamic brake lever in three notches and use the throttle; which may be realistic for new wide cabs but not for GP38s and SD40-2s. MSTS is a lot more realistic in this manner, but I still like Trainz even though it isn't that realistic in a few ways. As for train brakes and dynamics, both can be applied at once but in some cases it isn't the best idea. As stated above, dynamics take about 10 seconds to start up in real life, and are way more effective on newer locos, which can take you from 50mph to 1mph very fast depending on motive power. You would also want to brake with train brakes as you slow down to keep you from rolling in reverse.
Train brakes only affect the cars, and independent brakes only affect the loco. On passenger trains, independent brakes are not used much because it causes the couplers to bunch up and jolt everyone around in the passenger cars, definitely not comfortable. And, new locos have really good dynamics, such as the ES44s and SD70ACes, as well as SD90s and AC6000s. Hopefully a new feature in T:ANE will be more realistic brakes, because the brakes in Trainz are not very realistic, and compressors and the amount of air you have is also not taken into consideration.
JJstrainz
 
Last edited:
Railwayz said:
Retaining valves (also called grade controls or "grades" or chokes) were manually applied way back when. These days however most wagons have a built in restrictive valve on the exhaust port of the brake cylinder so that the brake release is retarded giving more time to rebuild brake pipe air while the train is still effectively under braking. Would that be hard to emulate in Trainz? This does make braking empty trains on the flat quite severe at times however.

Typically dynamic will drop out if brake pipe pressure is reduced so far that the Pneumatic Control Switch drops out leaving only air brake which would already be getting pretty low. Yes, dynamic only affects the locomotives. That is why you let the train gently bunch up against the loco's at the top of the grade. Dynamic alone will not stop the train, but modern locomotives can slow it a lot before air brake is needed if at all on gentler high speed grades.

Railwayz
Click to expand...

Thanks for your updated information. Obviously, there would have to be era-dependent differences in brake parameters!

:B~)
 
In my route, I place several reducing speedboards @ 2 miles distant a station stop 60mph, 40mph, 20mph, 10mph (5 mph is too slow, as are metric equivalents, as they cause a train to hunt and peck along like retarted pigeons at 15mpm, 2mph, 12mph, 4mph, 9mph ... etc ...)

I have all my turnouts aligned as the normal route path, and jus thit AI: "DRIVE" ... then when approaching a station platform I just hit: "STOP TRAIN"

If you do it right, it looks pretty slick, and realistic ... You can place visible signs or some other trackside asset, to show the exact location to apply brake.

Don't sweat the petty things ... or pet the sweaty thangs'
 
cascaderailroad said:
In my route, I place several reducing speedboards @ 2 miles distant a station stop 60mph, 40mph, 20mph, 10mph (5 mph is too slow, as are metric equivalents, as they cause a train to hunt and peck along like retarted pigeons at 15mpm, 2mph, 12mph, 4mph, 9mph ... etc ...)

I have all my turnouts aligned as the normal route path, and jus thit AI: "DRIVE" ... then when approaching a station platform I just hit: "STOP TRAIN"

If you do it right, it looks pretty slick, and realistic ... You can place visible signs or some other trackside asset, to show the exact location to apply brake.

Don't sweat the petty things ... or pet the sweaty thangs'
Click to expand...

This is no longer necessary in T:ANE. The AI is "smart" enough to start slowing down when they are preparing an approach to a signal or a station.
 
I have been looking at both freight and pass cars in Trainz. And Urban, Interurban, suburban rolling stock. And looking to single blocked, double blocked - referring to what is on each side of the wheel (or slot as they are sometimes called).

My understandings are:~

* Freight trains are single blocked on a single train brake pipe which has to be recharged and brake totally differently to
* Urban, Interurban, suburban, which tend to (but are not always) be double blocked, and have up to three or sometimes four braking systems (WABTEC EP + Rheo + secondary Air + Pneumatic or spring loaded Park Brake)
* the more modern Urban, Interurban, suburban stock may be disc braked, and again, a different braking proposition (snappy) but generally effective.
* Coal trains have the new ECPB systems in some places. I haven't read a description of this except on the Hunter Valley coal trains in NSW, Australia.
 
Last edited:
I try to use the same technique in Trainz that I use when running for real. If you crest a grade, gradually reduce the throttle, then activate your dynamic brakes. Give yourself a little speed cushion to allow your dynamics to become effective. On a long descending grade, make an initial, or minimum application while keeping your independent brakes released (hold down D key), adding the acceleration display to the HUD is a big help. Don't go straight to full dynamics, but work them back and forth to achieve a balance.
 
Full, or full, dynamics is applied, by shutting off the throttle, selecting half, or full dynamics, then slowly applying a desired throttle power to backflow electricity into the dynamics resistors and traction motors. Proper trainhandling is by educated guestimate, experienced judgment, and knowing beforehand where to throttle, where to cut off throttle and coast, and where to apply repetitive small trainline braking, how and where to slowly let the coupler slack run in ... this is by being trained by a superior engineer, who certifies that you too know the in's and out's of the route.
 
First you would apply a trainline service brake, and let any slack slowly run in, then apply dynamic braking as needed, as it is essentially like the air operated independent brakes effecting the loco's only. Essentially dynamics means that the resistance of electricity to the traction motors, puts a reverse load to them, which in turn is absorbed by the dynamic brake grids, which really turns the traction motors into an electrical generator backfeeding electricity.

On the 11 mile downhill "Slide" on the Appalachian Front Range, with a 1 mile long loaded coal train having 6 units total, it takes many service brake applications to keep the train speed below 35 mph, even with half, or full, dynamics on, in throttle power 6+.

Oftentimes, if not always a downhill freight slows, and stops, @ 2miles west of Altoona at the 27th st bridge. One time we saw 11 trains in an hour and a half from the Altoona walkway bridge, and you could feel the heat coming off the dynamic brake grids. Some of the wheels were smoking blue hot, with burning brake shoes.

https://www.youtube.com/watch?v=mCk21G2LR-M

https://www.youtube.com/watch?v=cXY2JZeK5Hw

https://www.youtube.com/watch?v=FBJlXVvtdn4

https://www.youtube.com/watch?v=tFamoOpk3Lc
 
Last edited:
cascaderailroad said:
even with half, or full, dynamics on, in throttle power 6+.
Click to expand...

Are you saying this in relation to trainz operation? Dynamic braking has nothing to do with throttle power and there isn't a half and full setting. The only thing I can think of is that you are trying to relate it to how default trainz (incorrectly) have a lever that you switch on and then up the throttle. Any item made by anyone with an understanding of how it actually works wont have this.
 
One of the brake systems I want to model in trainz is the load compensating equipment, normally with a freight wagon the brake ratio is set to the unloaded tare so under full brake cylinder pressure the wheels won't skid, the side effect is a fully loaded wagon looses lots of it's braking effort, the load compensating system has the brakes set for a fully loaded wagon so when the lever is set to L (Loaded) 350kpa goes into the brake cylinder, when the lever is set to E (Empty) air is diverted to a second air tank reducing the brake cylinder pressure to 190kpa so a light weight wagon of 18 tonnes tare won't skid the wheels and still have high braking effort when loaded to 76 tonnes (Vic/SA) 100 tonnes (NSW/WA).

for trainz a tag like (brake cylinder efficiency) in the script code could do this, for example see below.

Code: 
   if (msg.src == me)
      {
      if(queue1.GetQueueCount() == 1) {
                SetMeshAnimationState("load_compensating_lever", true);
                SetBrakeCylinderEfficiency 1.00 // Sets brake cylinder max pressure 350kpa
                }
     else
                {
                SetMeshAnimationState("load_compensating_lever", false);
                SetBrakeCylinderEfficiency 0.55 // Sets brake cylinder max pressure 190kpa
                }

      }
  }

the same could be done with the dynamic brake as the locos airbrakes are bailed during dynamic braking and only train brake is usable (Aus setup).

Cheers.
 
Last time I checked in the default Trainz cab, there was a handle with 3 settings: Dynamic brake: Off, Half, and Full

And an increased throttle power makes the train slow down in Dynamic Braking

If you put the handle on Full, it makes the train slow down much too quickly, which in real life would cause the coupler slack action to run in too quickly (much like applying independant brake on a 1 mile long loaded downhill coal train), hit you in the ars', and cause a "run in" derailment
 
Last edited:
Thats why I was asking. The default trainz cabs are nothing like real life. There is an operational difference that is plainly visible and probably not modeled by most trainz creators - with the exception of Jointed Rail of course. My first 'fix' of this inaccuracy can be seen on VMD products from circa 2004.

Also, in trainz there are 3 states for the motors:
0 = motoring or traction mode
1 = neutral
2 = braking mode.
There is no half or full dynamic brakes.

In my cabs I use mode 1 for "set/up" which most locomotives have as a state where the contactors switch over. In older style cabs I use it for selector "off" mode.
 
Last edited:
You must log in or register to reply here.

Similar threads

A
Tweaking braking for an enginespec - guidance needed.
Replies
7
Views
297
PortLineParker
P
J
Does TS 2022 have a much improved AI system over TANE?
Replies
9
Views
1K
IsambardKingdomBrunel
I
B
Recent 3ft gauge logging log cars?
Replies
0
Views
137
BraselC5048
B
O
Diesel Smoke When Waiting
Replies
2
Views
502
JCitron
J
U
Using TLR with Industry Link (a tip for making it work)
Replies
1
Views
213
UncleBuck
U
Back
Top