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#1 wmghobbs

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Posted 27 February 2006 - 07:06 PM

Here is a new regulator with notches to play with. The uneven spacing of the increments is meant to
to capture the difficulty of moving the lever when the pressure is higher on the boiler side than on
the dry pipe side. The first notch allows a little steam in the cylinders when drifting and keeps the
sound alive just a bit as well. I intend to make this standard on the new locos.

Regulator ( 0 1 0.02 0
NumNotches( 15
Notch( 0 0 Dummy)
Notch( .02 0 Dummy)
Notch( .20 0 Dummy)
Notch( .32 0 Dummy)
Notch( .42 0 Dummy)
Notch( .50 0 Dummy)
Notch( .58 0 Dummy)
Notch( .65 0 Dummy)
Notch( .7 0 Dummy)
Notch( .75 0 Dummy)
Notch( .8 0 Dummy)
Notch( .85 0 Dummy)
Notch( .9 0 Dummy)
Notch( .95 0 Dummy)
Notch( .99 0 Dummy)
)
)

There are two sets of coupler settings below for you to test with. Both are intended for use with freight cars in the weight range of the
TOC equipment in the StL&NA sets and not with heavier modern equipment. The settings were designed around the C and D coupler
data found in the 1922 Locomotive Cyclopedia, both for travel and tolerances. I've tried to keep the break force as low as
possible, but you may find it necessary to change from 1.2e6N or 1.6e6N to 1.2e7N if you have problems. On the Test Track
route, I've found one node that I've had trouble getting across period (at the top of the 5+% grade).
Without going too far into the physics of damped springs, I worked trying to accomodate both the lightest cars in
the route (3t - 5t) in the first stage and the heavier (40t - 50t)cars with the second stage. The heavier cars are
underdamped in the first stage, but handled properly if forced to the second stage (beyond 5cm). Real couplers are set so that
weak collisions are handled without compressing the springs fully. Here, the first set of values is intended to handle these
collisions while the second set are used to replicate the stronger collisions that fully compress the springs. This is done
by making the setting strong enough to exceed the break force of the coupler over a reasonable distance beyond the second R0
value. I looked graphically at the slopes of the force lines with various settings to help me visualize how these will
behave as displacement from the center proceeds.
When couplers are being extended, the stiffness is sufficient that the locomotives maximum tractive effort will not cause
the springs to extend beyond a realistic distance.
NOTE: no attempt is being made to "improve" front coupler performance with these settings. I am convinced that we will never
square that circle.
FINAL NOTE: Best results in coupling can be expected if the train is moving under 4mph and decelerating (expected speed is
below the current speed). This reduces the forces acting on the couplers greatly.
Coupling (
Type ( Automatic )
Spring (
Stiffness ( 4.7e5N/m 1.7e7N/m )
Damping ( 7.5e4N/m/s 1.65e6N/m/s )
Break ( 1.2e6N 1.2e6N )
r0 ( 0cm 5cm )
)
Velocity ( 0.11m/s )
)
Coupling (
Type ( Automatic )
Spring (
Stiffness ( 4.7e5N/m 1.7e7N/m )
Damping ( 7.5e4N/m/s 1.65e6N/m/s )
Break ( 1.2e6N 1.2e6N )
r0 ( 0cm 5cm )
)
Velocity ( -0.11m/s )
)


Coupler test 2. More play.

Coupling (
Type ( Automatic )
Spring (
Stiffness ( 3.0e5N/m 1.15e7N/m )
Damping ( 6.0e4N/m/s 1.36e6N/m/s )
Break ( 1.6e6N 1.6e6N )
r0 ( 0cm 5cm )
)
Velocity ( 0.11m/s )
)
Coupling (
Type ( Automatic )
Spring (
Stiffness ( 3.0e5N/m 1.15e7N/m )
Damping ( 6.0e4N/m/s 1.36e6N/m/s )
Break ( 1.6e6N 1.6e6N )
r0 ( 0cm 5cm )
)
Velocity ( -0.11m/s )
)

I have a set of coupler values for true link and pin couplers, but they are not a joy
to work with - as the real one's were. Instead of 200,000lbf capacity, they are limited to 50,000lbf and alternate
between real slack (the links loose) and going for the maximum stiffness.

Bill Hobbs

#2 atsf37l

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Posted 28 February 2006 - 08:01 AM

Oh boy! A new throttle to try! I think I'll do my C-21 first. She's at Cascade Tank ready to head for Silverton so that tough grade at MP 487 might just be a good test. tongue.gif

I might try your coupler settings on some of these D&RGW/RGS narrow gauge cars since they are about the same size as the TOC stuff. I have been doing a lot of playing with the numbers trying to get the weights and braking rates right for them. Most cars offered have full size standard gauge braking rates (50kN MaxBrakeForce). On a string of 11 ton cars that means full screeching stop with a two to three pound reduction! I've been playing with 10kN MBF and can get the train to hold speed with an eight lb reduction and slow gradually with 12 lb off the clock. 20 lb will bring you to a nice steady deceleration and stop. I have also reduced the handbrake force from 35kN to 5kN (more than enough to hold a stationary 11 ton car even on a 4% grade) which allows me to use the handbrakes as retainers when coming down Keystone, Dallas Divide or Cumbres' west slope. This allows you to actually go to full release and trainline charge without running away on the hill before you are ready for another holding set. I can drop a 20 car train down Keystone with a C-16 (Bazza beta tongue.gif ) holding 10-12 mph with ease. Attentive ease, but ease. Same for a 40 car stock train and a K-36 on Cumbres. Sweet. biggrin.gif

#3 copperpen

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Posted 28 February 2006 - 11:59 AM

Bill
Thanks for your work on these settings. I will try them out later on. The front coupler has never been a problem for me while running steam, minimum on the Johnson, crack the throttle and just drift away. It is those smelly kerosene cans that have the real problems and the only way to deal with them is a really low power setting on the first notch, and not much higher on the second one.

Mervyn

#4 wmghobbs

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Posted 28 February 2006 - 03:21 PM

Herb,
I did a quick calc on a braking ratio for an 11t car. You might be surprized at the results. The brake force -- even assuming a generous 20% adhesion for brake shoes -- would be only 5kN! If you have Excel and don't have my Steamloco Setup sheets, I can send you the spreadsheet that calculates braking forces.

Bill Hobbs

#5 atsf37l

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Posted 28 February 2006 - 03:32 PM

I do have your tables, Bill. No, I'm not surprised. I am trying to get a ratio that works reasonably well. 5kN might be a little harder to control than I'm willing to tackle. tongue.gif The problem, of course, is that I like to pop out and look at the train a little bit and not be "tied" to the brakestand. I put F5 up but sometimes tend to look only at the train! laugh.gif

10kN gives me better control while I'm climbing about on the running boards.

All that said, I might just try a little 5kN on a string of cars just to see how they handle. Bottom line is that the "as delivered" setups on these things are WAY out of whack with the 50kN stuff.

#6 S. Weaver

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Posted 28 February 2006 - 04:05 PM

QUOTE(atsf37l @ Feb 28 2006, 10:01 AM)
... This allows you to actually go to full release and trainline charge without running away on the hill before you are ready for another holding set. I can drop a 20 car train down Keystone with a C-16 (Bazza beta tongue.gif ) holding 10-12 mph with ease. Attentive ease, but ease. Same for a 40 car stock train and a K-36 on Cumbres. Sweet. biggrin.gif

Love it, Uncle Herb. Yer outta control. tongue.gif

Now. Let's see, scoop these values out and get 'em simmering. Tinker with the handbrakes ... Sounds like initiative for a new St.L&NA activity, if I can find the time. sad.gif

#7 wmghobbs

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Posted 28 February 2006 - 05:40 PM

Steve,
I was reading at the NG Discussion Forum and was surprized to see your name show up along with several photos of a very nice looking freight pulled by #90. Here is the reference:
http://www.ngdiscuss...k.pl?read=71727

Bill Hobbs

#8 atsf37l

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Posted 01 March 2006 - 08:53 AM

QUOTE(S. Weaver @ Feb 28 2006, 04:05 PM)
QUOTE(atsf37l @ Feb 28 2006, 10:01 AM)
... This allows you to actually go to full release and trainline charge without running away on the hill before you are ready for another holding set.  I can drop a 20 car train down Keystone with a C-16 (Bazza beta  tongue.gif ) holding 10-12 mph with ease.  Attentive ease, but ease.  Same for a 40 car stock train and a K-36 on Cumbres.  Sweet.   biggrin.gif

Love it, Uncle Herb. Yer outta control. tongue.gif

Now. Let's see, scoop these values out and get 'em simmering. Tinker with the handbrakes ... Sounds like initiative for a new St.L&NA activity, if I can find the time. sad.gif

Actually, setting a handbrake or two on things like the "hot footing" consist makes it very nice indeed to handle a train down the Seligman hill! Been there. Done that. Got the T-shirt. laugh.gif

Actually, I did it on StL&NA before taking it to Colorado! Learned the skill in the Ozarks, perfected it in the San Juans. tongue.gif

Totally out of control!

#9 wmghobbs

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Posted 01 March 2006 - 04:00 PM

Herb,
I've run plenty of tests with these brake settings and have learned how to control the trains. Its essential that you do not let the train accelerate beyond the speed you want to maintain going down hill before you start setting the brakes. With uneven grades (like Seligman -> Pender), it may be necessary to open the throttle a bit at spots to avoid releasing brakes.
Unprototypically, the hand brakes are additive to the real brakes. 5kN hand brakes + 5kN air brakes = 10kN of final braking power.
I have tried playing with the retainers, but haven't succeeded in getting them to work. that doesn't mean they don't work, only that I haven't figured it out in the same way I missed putting the token "Dummy" in the throttle to get notching to work properly. Capt Bazza showed me what I missed.

Bill Hobbs
blush.gif

#10 S. Weaver

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Posted 02 March 2006 - 04:29 AM

QUOTE(wmghobbs @ Feb 28 2006, 07:40 PM)
I was reading at the NG Discussion Forum and was surprized to see your name show up along with several photos of a very nice looking freight pulled by #90 ...

Yes, Bill. That was on the 17th. The XM in front of the caboose is 103 years old this year.

#11 S. Weaver

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Posted 02 March 2006 - 04:29 AM

QUOTE(wmghobbs @ Feb 28 2006, 07:40 PM)
I was reading at the NG Discussion Forum and was surprized to see your name show up along with several photos of a very nice looking freight pulled by #90 ...

Yes, Bill. That was on the 17th. The XM in front of the caboose is 103 years old this year.

#12 wmghobbs

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Posted 02 March 2006 - 05:33 AM

I wish the Friends had the where-with-all to keep their equipment in that condition.

Bill

#13 atsf37l

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Posted 02 March 2006 - 09:15 AM

QUOTE(wmghobbs @ Mar 1 2006, 04:00 PM)
Herb,
I've run plenty of tests with these brake settings and have learned how to control the trains.  Its essential that you do not let the train accelerate beyond the speed you want to maintain going down hill before you start setting the brakes.  With uneven grades (like Seligman -> Pender), it may be necessary to open the throttle a bit at spots to avoid releasing brakes.
Unprototypically, the hand brakes are additive to the real brakes.  5kN hand brakes + 5kN air brakes = 10kN of final braking power.
I have tried playing with the retainers, but haven't succeeded in getting them to work.  that doesn't mean they don't work, only that I haven't figured it out in the same way I missed putting the token "Dummy" in the throttle to get notching to work properly.  Capt Bazza showed me what I missed.

Bill Hobbs
blush.gif

I am familiar with the technique: Put on a set at the top of the grade before you get up to track speed and as track speed increases increase the set until the proper speed is maintained then hold that set all the way to the bottom, using the engine to pull against the brakes if the speed drops too low. Fine. I can do that.

But it is my experience that this is not the way trains are handled in real life. Air systems leak and if you tried this on, say, Cumbres Pass, you'd be out of air before you reached Coxo. In the real world you must recharge the trainline and that takes full release. On a 4% grade you can't go to full release without running away unless you come to a complete stop each time. The recharge time would be about right from dead stop to around 20 MPH. tongue.gif

The solution is retainers. In real life, retainers maintain the braking on the cars while the engineer recharges the air line for the next set by holding in the air pressure on the bleed line from the brake cylinder. This allows the brakes to gradually release rather than go into full release.

In MSTS we dont have retainers. rolleyes.gif So what to do? The only alternative is handbrakes - low set handbrakes. I have my train brakes set thus:

Brake_Train ( 0 1 0.1 0
NumNotches( 6
Notch(0 0 TrainBrakesControllerReleaseStart )
Notch(0.2 0 TrainBrakesControllerRunningStart )
Notch(0.4 0 TrainBrakesControllerSelfLapStart )
Notch(0.5 1 TrainBrakesControllerApplyStart )
Notch(0.9 0 TrainBrakesControllerFullServiceStart )
Notch(1.0 0 TrainBrakesControllerEmergencyStart )
)
)

Using a normal 10.12 M ton (11.15 I tons) empty freight car set with 10kN MaxBrakeForce on the train brakes and 5kN on the handbrake, make a consist of 20 of those cars. At the top the 4% grade of your choice, set the handbrakes on three of those 20 cars, spread throughout the train. Kick off the air and start off down the hill. Let's use Cumbres as an example. Speed limit going down the hill is 18 MPH. Approach 18 and take a 12 lb set (or whatever it takes to see a reduction in speed - results may vary! tongue.gif ). Let the train settle down to a speed of around 15 MPH. Kick off the air and recharge. Notice that, instead of charging ahead to 20-25 as you would normally expect the train holds it's speed, increasing gradually while you get a full recharge. As you approach 18 MPH again you are now ready for another set. Repeat the above until you reach the sag at Coxo, then be ready to start the cycle over again when you pass the phone booth, all the way down to the flats north of Chama. As you roll into Chama you can turn off the retainers (handbrakes) in order to pull into the yard tracks.

The number of cars with handbrakes set for safe control will vary with different equipment so experiment. You may only need two, you might need four or five. The above represents my experience.

Using this technique I get a very realistic operation of a full train on a 4% grade. The brakes do all the work and the engine's steam doesn't have to be used for anything but the compressor. wink.gif

This is more work for the engineer than the "set-em and drag against em" method but coming down a major hill should be work. Pop over to the NGDF or the Goat and ask Coker or Earl if they nap on downhills! laugh.gif But it sure does simulate what a real engineer does on the downhill side and that, to me, is what its all about. tongue.gif
______

To give credit where credit is due, I got this idea and method from Brad Brown of 3DTS who has an activity using handbrake "retainers" on one of his Tehachapi Loop enhancements. I was having trouble with runaways on Keystone on the RGS when I remembered this "retainer" operation from Brad and used it to solve my problem.

#14 atsf37l

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Posted 02 March 2006 - 09:16 AM

Oh, by the way, I really like your new throttle! biggrin.gif My C-21 is real happy with it. I am anxious to try it on some 3751 class engines!

#15 wmghobbs

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Posted 02 March 2006 - 03:19 PM

Herb,
I like the idea of using handbrakes for retainers. I'll do some experimenting with that while I am testing sounds in the next few days.
BTW, there is a variable for setting brake leakage, but my initial experiments with it didn't show any results. It was in the braking section of the Tech Docs for vacuum brakes, so I'm not sure if it was intended to work with air brakes.

On long grades I too have found it necessary to bring the train to a stop and, in my case, use the engine brakes to hold the train back while the brake line recharged. I found that on some grades, setting hand brakes was essential to keeping the train stopped, but I didn't ever thinking of setting the handbrake values to function as retainers. I see you are using 50% of normal braking force for the retainer.

As far as the brake forces go, your indicated speeds may be the reason my braking forces don't work well for you. I try to keep speeds down under 10mph descending steep hills with this old equipment. I've found these settings don't work well with speeds over 15mph -- you risk losing control.

Bill

#16 laming

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Posted 03 March 2006 - 08:33 AM

Well, as one that runs trains almost weekly using an old 6L type brake valve, there's some important things to remember:

* In the real world, leaks in the train line means that once a good set is applied, the leak is causing MORE brakes to apply in the train line.

Remember: How do you apply brakes with automatic braking? You reduce pressure in the train line.

With the 6L valve, there is a "work around" you likely won't find in any manual: You can "ride the hump" with the brake valve and actually perform a partial recharge/release of the brakes. Once sufficient air has recharged to reduce the brakes applied, you go back to LAP postion. Use with care.

I'm uncertain of how brakes were handled with "Straight Air". (i.e. An air system prior to the Automatic Brake system, of which the 6L is a part of.) What I do know about Straight Air is that if the train line is severed, complete loss of brakes results.

I don't think modeling Straight Air is possible with the MSTS codiing.

Bill:

In your studies, have you been able to ascertain when the switch to Automatic Air begin to take place in sincerity?

#17 atsf37l

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Posted 03 March 2006 - 09:50 AM

Not Bill but an answer anyhoo. From my reading I see 1903-04 as the narrow gauge changeover dates for knuckle couplers and auto air. This timeframe is for both the D&RG and RGS. Most standard gauge lines were done before then, IIRC.

Right on the increased application with the leakage, which required the engineer to release and reset to keep from stalling on the hill. Without retainers, this could mean running away because the air line would be too low to get a set. You have to have air in the lines in order to be able to reduce the pressure and activate the triple valves to send air from the reservoirs to the cylinders. And you have to have recharged air in the reservoirs on the cars to charge those cylinders. It gets too easy on a long steep hill to get the pressure down close to atmospheric. At that point the only solution is to find a soft tree or snowbank into which to jump. laugh.gif

Correct me if I'm wrong, oh throttle jockey, but isn't it true that a large leak, as referenced above, will set more air on the cars but a slow leak will merely drain the system without "tickling" the triple valves? Mostly thinking of old K-brakes here. This is where my argument with a single set on a long hill comes in. I don't think, in real TOC or narrow gauge life, that set would hold. Gradual leakage would ease off on the brakes at the cylinder and rob the trainline of needed pressure from which to take another reduction. Trees and snow again. tongue.gif

I love these discussions of how the prototype works! biggrin.gif

#18 laming

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Posted 03 March 2006 - 10:36 AM

Hi Herbie:

I was thinking that standard gauge useage preceded narrow gauge "drop dead dates" by a few years. For example, I think 1899 was the drop dead date for knuckles on standard gauge interchange cars.

I suspect that in my target era of 1893 for the Ozark Northern, straight air SHOULD be used. However, we likely will have to settle for extremely tweaked MSTS auto air.

As for my comments above. The grades I deal with are not long enough to cause concern for depleting the main reservoir. I suspect it will be an entirely different situation if I was facing upmteen miles of 4% instead of the short stretch of same that I deal with.

You can "ride the hump" on such situations as I mentioned, but doing so on the long term will depleat the main reservoir and the old addage of "pi**ing off the air" comes into play. In otherwords, find the snowbank!

Unfortunately, I also am not experienced running K brakes (IF that's what the older freight equipment at the ES&NA was equipped with) enough to be able to add significant insight into that aspect of the discussion.

As for air and descending grades:

It is pretty common knowledge on a working railroad that if you've overset the brakes and have ANY doubt as to the ability to release/recharge and maintain control: Bring the train to a stop and hold in place through whatever means necessary to recharge the air.

One would be surprised how you have to do that on the "real ones". For example, a good friend of mine worked for a Class 1 that runs hefty grades. He was an engineer trainee on one of his first runs. He was called to run helpers on a huge coal train.

With his seasoned engineer beside him (the prototype for "Sarge" in the StLNA route), they dropped off "the mountain". The head engineer was on loan from a flatter portion of the railroad and was unfamiliar with descending such a heavy grade. The head end had already made a couple of sets/releases and was on the verge of pottying off his air. The dyanamics weren't going to hold them and they had already exceeded 50 MPH and well past the speed limit.

The young man looked at Sarge with grave concern on his face.

Sarge yelled across the careening cab: "Plug'em!"

That he did, and 2 miles later they were sitting still without sufficent independant brake to hold the train in place for a recharge.

Seeing an opportunity to teach the aspiring young engineer, Sarge asked: "What will you do now?"

Thinking for a moment, the young man said: "Well... I'd radio the head end to put 'em in reverse and back agin' 'em, and I'd do the same an' pull on 'em until we git some air back."

Sarge then said: "That's exactly what I would do. Now do it".

20 minutes later, they were safely on their way with a humbled head end engineer.

Thus far, MSTS has done little in the way of replicating such intricacies of running trains. That was one of the reasons I wanted to do some things differently with the VSC routes. The (eventually) upcoming Ozark Northern hopes to take it to a new level.

#19 atsf37l

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Posted 03 March 2006 - 12:37 PM

Great story! Until I got comfy with the handbrakes/retainer operation I had to do just that a few times on Cumbres! Shudder to a full stop and put on full reverse or as much as she'd take with sand and no slipping. Then kick 'er into full release and slowly begin moving down the hill against the pressure in the cylinders, because one K36 couldn't hold, let alone move, 40 cars up a 4% grade. That's when the knees hit the boards and you pray you can get a full charge before you pass 15 MPH or so. Of course I could have set enough handbrakes to hold the train but where's the fun in that? cool.gif

Ozark Northern sounds like lots of enjoyment for the masochistic engineer! blink.gif

#20 wmghobbs

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Posted 03 March 2006 - 03:21 PM

The Safety Appliance Act of 1893 speed the conversion to air brakes up so that by 1900, they were considered standard equipment on interstate RRs (according to John White in "The American Freight Car").
The Colorado Midland (whose equipment we are working on now) was converted before the Act was passed apparently.
Depending on the setting used, retainers keep 10 - 20lbs of pressure (20% - 40% braking force with 50lbs being the max) in the cylinder while the brake line is recharging, thus keeping the brakes partially set.
I didn't see much evidence of straight air being in widespread use in White's book. Apparently as late as the late 1880's, many freight cars were not equipped with much more than friction brakes or hand brakes -- in order to cut costs.
I wonder whether it would be of interest to try a train with only handbrakes? Oh yeah, and link and pin couplers.

Bill Hobbs
laugh.gif