[ebnertra000]

The hotbox procedures I found in the attached .pdf file are on pages 15-18. I also found a Soo Line set of rules from 1984 which I'll have to upload in a bit. Those I could fit in a screenshot, but the attachment option doesn't like the image

Attached File(s)

•  4888BNSF-Spcl systm instructions.pdf (3.78MB)
  Number of downloads: 604

[longiron]

Here are B&O's steam era guidelines for train handling in the friction bearing timeframe:

If temp was below 0 degree F - add 6 tons trailing weight per CAR

If temp was between 0 - 20 degree F - add 4 tons trailing weight per CAR

If temp was between 20-35 degree F - add 4 tons trailing weight per CAR


Regarding Steam locomotive themselves, I found this

I have added a "fudge factor" to my steam friction calculations. This is something that Joe Realmuto's excellent calculator does not account for.

According to numerous references in my collection of books pertaining to locomotive engineering, construction and operation,when calculating steam locomotive friction (resistance) an additional factor must be added to the standard Davis formula.

The Davis formula for locomotives is as follows, and is the basis for Joe's calculations ( and real world tonnage ratings ):

R=1.3T + 29N + 0.03TV + 0.0024CAV

Where
R=Resistance in lbs
T=locomotive weight in (US 2000lbs) tons
N=Number of axles
V=Velocity in MPH
C=Coefficient of friction ( air resistance )
A=Front area of locomotive in square feet

Now, here is the missing bit, quoting Ralph P. Johnson in "The Steam Locomotive":

"In calculating total resistance for the steam locomotive it is customary to use the same values for journal, flange and air resistance as the electric locomotive, but to add a constant amount for all speeds of 20 lbs per ton of weight on the driving wheels to cover the internal machine friction of the locomotive between the cylinders and the driving axles. The total gives the resistance at the rail."

(I can't cite the exact reference right now, but in a newer book in my collection it states that it is permissible to reduce this factor by 20% for engines with lightweight roller bearing rods ( N&W J Class and the last five A Class 2-6-6-4's 1238-1242 for example) and by 50% for those equipped with poppet valves and Franklin Rotary Cam valve gear (PRR T-1 and Q-2 Duplex locomotives for example ))

So the modified Davis calculation may be expressed as follows:

R=1.3T + 29N + 0.03TV + 0.0024CAV + 20D

Where D=the weight on driving wheels in tons.

Now, how do I translate this into the sim, and what is the effect of all of this stuff?

I want to use Joe's calculator and save myself the aggravation of hand calculating the Friction parameters for each engine so I came up with an idea. if I take the factor 20D, and divide it by 29, I come up with a number of "phantom axles" that when added to the total number of actual axles, will cause the calculator to add the additional resistance. I can bore you with the math, if anyone wants to see, or you can take my word for it.

Level track numbers for Union Pacific Big Boy where T=381 N=12 V=5 C=1 A=120 20D=5400, and the resulting Friction parameters from Joe's calculator:

Without the fudge factor: 907.65 lbs resistance:

MSTS Friction Value:

3750.8N/m/s -0.10 1.3mph 34.957N/m/s 1.631

Rolling Stock Type: Steam Freight Locomotive
Axles:12 Mass: 345.6 tonnes Frontal area: 11.15 m Cd: 1.00
Davis=Fcalc speed: 70 mph
RMS Error(2 mph to 80 mph): 44.6760 N
Maximum Error(5 mph to 80 mph): 92.57 N @ 80 mph
English Davis Equation(V-mph, R-lbs): R = 843.22 + 11.4287 V + 0.288042 V
Metric Davis Equation(V-m/s, R-N): R = 3750.81 + 113.7197 V + 6.411361 V


With the fudge factor (186.21 phantom axles): 6307.65 lbs resistance:


MSTS Friction Value:

27771.0N/m/s -0.10 1.7mph 11.096N/m/s 1.950


Rolling Stock Type: Steam Freight Locomotive
Axles:198 Mass: 345.6 tonnes Frontal area: 11.15 m� Cd: 1.00
Davis=Fcalc speed: 66 mph
RMS Error(2 mph to 80 mph): 247.2583 N
Maximum Error(5 mph to 80 mph): 506.06 N @ 6 mph
English Davis Equation(V-mph, R-lbs): R = 6243.16 + 11.4287 V + 0.288042 V�
Metric Davis Equation(V-m/s, R-N): R = 27770.96 + 113.7197 V + 6.411361 V�


As you can see, the there's a dramatic increase in the Friction parameters for the second calculation. (of course, the NALW Big Boy is in 2 parts in MSTS, so you would calculate each part using 1/2 of the "real world" values. )

The result is that the locomotive now pulls the "real world" rated load up the proper grade at a proper speed ( a walk instead of a trot, 8-10 MPH vs. 15-17 MPH ).

I have created 2 slopes in the sim, 1.14% to represent the Wahsatch grade out of Ogden and 1.55% to represent the "old line" over Sherman Hill, Westbound from Cheyenne.

The real world adjusted tonnage ratings were 4450 for the 1.14% and 3250 for the 1.55%, both with a car factor of 5.

The NALW Big Boy now performs prototypically on both grades with the rated load. It also handles a 3600 ton fruit block up the 1.14% at about 15 MPH as was the case in real life.

These are adjusted tonnage ratings. If anyone needs an explanation as to what are "adjusted tons", "car factors" and how to calculate, ask and ye shall receive. I can also provide some tonnage rating info for certain engines on certain grades, and am in the process of calculating ratings for various engines on various routes in the sim.

[ebnertra000]

Alright, here's the other set of procedures. Soo Line 1984:

Attached thumbnail(s)

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[steamer_ctn]

The calculation of wheel bearing temperature is like all railway related topics quite a complex subject.

In broad terms, heat is generated in the bearing as a consequence of the friction in the bearing. Heat is also dissipated from the bearing. Under normal operation when the heat generated in the bearing matches the heat dissipated, the bearing temperature will reach a steady state. This temperature is influenced by a number of different factors, including bearing type, bearing design, lubrication, ambient temperature, etc.

In OR MG v23 the start of a representative bearing heat model has been inserted. This model allows the bearing to heat up when the train is running, and should reach a steady state value at some point. When the train is running at slow speed the heat dissipated will be greater then the heat generated, and thus the bearing will cool down. The bearing temperature is monitored in the Forces information HUD with the introduction of a new column called "Bear Temp"..

On occasions, due to a fault developing in the wheel bearing, it is possible for the generated heat to far exceed the heat being dissipated, and in this case the bearing can significantly overheat, and typically this is known as a "hot box".

Depending upon the severity of the hot box the axle can ultimately fail on the wagon, and it is not unknown for wheels to fall off a wagon, causing derailments, etc.

A scenario has also been included to allow a hot box to be triggered in OR. This feature only works in activity mode, and the "Activity Randomization Level" needs to be set between 1-3 to ensure that the hot box is triggered. A hot box may then be randomly generated (probability of occurring will depend upon randomization level) when the activity is initially loaded. The hot box will be actually triggered at some random time within the first 66% of activity duration time quoted in the activity. Once triggered the wheel bearing will start heating at an accelerated rate beyond the normal operating temperature of the wheel bearing.

Currently this feature only "alarms" and doesn't make any changes to OR. The next patch to be added for this feature will make some adjustments to the resistance of the train as the bearing moves outside of the normal operating temperature. Similarly a change in resistance will be linked to a hot bearing, and its ultimate failure.

[darwins]

Special effects too? smoke? flame?

It must have been common and accepted in UK that if a goods wagon failed it was cut out of the train and left in a siding. (Such wagons were known as cripples.)

There are no references to the problem in the LMS Rule Book, but the General Appendix has the following related information:

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

https://i.imgur.com/x7kIHlZ.jpg

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

[steamer_ctn]

 darwins, on 02 June 2019 - 10:28 AM, said:

Special effects too? smoke? flame?

Flame is probably beyond the capability of OR at the moment (as far as I am aware).

However it might be possible to include some smoke effect. What would this look like, do you have any video footage as an example?

 darwins, on 02 June 2019 - 10:28 AM, said:

It must have been common and accepted in UK that if a goods wagon failed it was cut out of the train and left in a siding. (Such wagons were known as cripples.)

What happens if a hot bearing is discovered mid section? How does the wagon get "cut out"?

Thanks

[steved]

I've never seen one flame out, unless the journal cover is opened, but they sure put out a bunch of black oily smoke.
They would usually pull the waste ( the pad in the journal box used as a wick to carry the oil to the bearing) let the car sit a while so the bearing would cool and add oil and waste to lubricate it so it could be moved.
I remember having waste hooks as standard tools into the 70s.
If the car is safe to move it's set out at the first available siding or spur where it can be accessed and repaired. The movement is made at restricted speed and the cars behind it are cut off (uncoupled) to prevent them from following the damaged car into the ditch if that happens.

Fun times
Steve

[steamer_ctn]

 steved, on 02 June 2019 - 04:02 PM, said:

They would usually pull the waste ( the pad in the journal box used as a wick to carry the oil to the bearing) let the car sit a while so the bearing would cool and add oil and waste to lubricate it so it could be moved.
I remember having waste hooks as standard tools into the 70s.
If the car is safe to move it's set out at the first available siding or spur where it can be accessed and repaired. The movement is made at restricted speed and the cars behind it are cut off (uncoupled) to prevent them from following the damaged car into the ditch if that happens.

Thanks for the feedback.

Could you expand on the above. For example how long did you have to wait? What was the restricted speed limit, etc? Was this a standard operating rule?

Thanks

[ATW]

[ebnertra000]

BNSF special instructions seem to indicate 30mph as the max. speed until a car with a faulty bearing can be set out. Mind you that this is for roller bearings. I can try to dig up a speed for friction bearings when I get home