Bnsf Es44c4 Automatic Brake Inadequate?

I'm not able to reproduce what you are stating. I just tested stopping the train in the OP. At the 0.3% uphill gradient around Victorville I made a minimum reduction with power in N4 then slowly reduced the throttle (initial speed 40 mph). At 10 mph I made a further reduction to 80 psi and the stopping distance was ~ 5200 feet. This is slightly shorter than the stopping distance described by the engineer in this thread.

"I have measured this time after time using my watch and Fred and the footage counter. If you set a minimum to 8 psi on an 80-110 car train it takes approx 8-9 seconds for the air pressure on the FRED to start dropping. At 40 mph you have traveled 500-600 ft. It takes another 20-30 seconds for the brakes to get seated and for cylinder pressure to build and for the brakes to really begin dragging. You have gone a total of 2000 ft or more. If the brakes are wet or snowy you can about double that time and distance. How much longer it takes to stop depends upon grade, TOB, etc. At Sheridan depot I set the minimum at 40 mph about 6,000 ft out and in number 3 or 4 throttle. As the air takes hold I reduce to 2 or 3. (power braking above #4 is illegal). It is uphill about 0.5% but a short steep grade of about 0.8% 2500 ft from depot, then the headend tops over a slight downgrade a few hundreds feet before the depot. Usually all this brings you to a halt at the depot door (6,000 ft). But with heavy trains you need to increase the set to 10-11 psi 600-1000 ft before the stop. With grain empties or coal empties I start about 4500-5000 ft from the depot instead of 6000-6500 ft."

The train described in the quote is a bit longer and probably (?) doesn't have rear DPUs but on the flip side it probably has a lower TOB since the train in the OP is almost maxed out and I did this with a train that wasn't fully charged from the starting state of the initial reduction so I think the behavior is pretty realistic. Of course with dynamic brakes I could cut that stopping distance down quite a bit. I'm also not able to reproduce the runaway described in the OP. I was able to control the even heavier (and higher TOB) grain train down the (not supported) M3 with a 16-17 psi reduction and about 60% dynamic brakes. Expecting to have to use less air than this on a 3 % + gradient with a 14500 ton 143 TOB train doesn't seem realistic. From my understand there's a rule of thumb used by engineers running over Tehachapi and Donner pass to set 1 pound per 10 TOB on the ~ 2% grades there. Basic physics would imply that you need ~ 50% more brake force on a 3 % grade.

 

Track 3 is downhill only but the power ratio should be higher.

 

Tons per operative brakes is a complicated thing to equate on intermodal trains, fyi. What you think it would be is not what it often is.

 

Power braking above notch 4 is not illegal on all railroads. The Class 1 I work for actually doesn't even have a notch limit. I've made a 24 psi reduction on the ES44C4's with a 4,000 foot long train and after 1 minute the train barely reduced speed by 5-7 mph with throttle at idle. A 24 psi reduction on a train of that length should react better than it does.

 

I wonder, do nowadays US railroading still doing stretch braking? In any case such as bring a train to a complete stop or initiate to negotiating 30 mph tight curve after doing track speed of 60 mph.

 

Not really in that case. But when stopping certain trains, yes.

 

Yeah, that's pretty bad. Unfortunately the trains without rear DPUs have much worse brake performance in the game because these trains don't actually apply fully on the rear (can be seen in Simugraph and also on the rear PSI readout). All I can say is that currently the air brake physics becomes less realistic above some number of cars (around 40). Technically all this is testable in the game. Compare the rear PSI readout on a 20-30 car local train vs a 80-100 car train without rear DPU. It is also possible for the rear to release uncommanded due to some of these issues (this has been improved in CJP but it is still possible as some people have reported). For trains with rear DPU the problems are about reduced in half since the application is made on both ends but it's still there, just diminished. I tuned the brakes based on Net Braking Ratio (NBR) of the real world counterparts and used the rule of thumb I mentioned above as a "sanity check", together with input from real world train engineers.

Even if the airbrakes applied equally on all the cars in the game (on long trains) it may be that the brake performance is still wrong. All I can say to that is that I can only work with the data I have and in the US trains seem to be guarded like Fort Knox (at least for the last 21 years and 1 day).

 

Why not try running this like sand Patch grade Sand Patch to Cumberland Downhill Dynamic and Auto Brakes. Worst if still speeding up Downhill Dynamic Independent and Auto Brakes.