Western Railroad Discussion > Train handling questions, quite specific on mountain grades

Hello!

I am a german engineer and for more than 10 years I operate on mountain grades (up to 3,8% through the Alps (via Austria to Italy). I added some pictures so you get an idea.

About a year ago I came across a simulator called Run8 - obviously I know, that no simulator, even a professional one, comes close to train handling in reality - usually the professional ones are just good enough for training purposes.
However, having that in mind, I am told for a "game", Run8 comes quite close to reality. There are quite a few "real" railroaders in the Run8 community that approve of that.

Finally to my question(s):

You run a ~8000t, 2,7hpt train with ~80 TOB in 3x2 (ES44's for example) down a 2,2% grade like Tehachapi summit to Ilmon just to give an example.

- What kind of brake pipe reduction would usually be sufficient? In theory, the DB should hold a train like this nearly by itself which of course is not in accordance with the rules as far I can tell. So the engineer would use the DB plus a minimum 6PSI reduction or more?

- Let's say you have to stop on the grade because of a meet. Do you keep the (minimum?) reduction and just use all of the DB to slow down and the independent brake as you come to a stop or do you apply more? If stopped, how much reduction to keep it safely stopped? I think I read something about a 15PSI reduction?

- Which brings me to the next question about recharging: You stopped for the meet, now it's time to go. As I know, releasing brakes on a grade is generally no good idea. But we have a DPU and good DB. Would the engineer in this case release and recharge the brakes (and let the DB do the work until recharged) or would he drag the train with applied brakes until it moves? Retainers or handbrakes would be an option, I know - But when I visited the Tehachapi pass in 2011, I did not observe a conductor applying any of those when a meet occured.

That's all for now, thanks for replies in advance!

Greetings from Bavaria, Kilian

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I don't run on Tehachapi but I do run on Donner. The grade is very inconsistent. When I tip over at the top I will put in a minimum set and balance my train against the dynamics. I usually will run with enough air set to keep the dynamics working in dynamic 4. Depending on the train I might have to go as deep as a 12 lb set. If I need to stop I will use the dynamics to stop the train and hold my set. To get going again just ease off the Jam and let the dynamics start to come up as the train rolls out, sometimes I will push with the dpu to bring the train up to speed. I will release on the grade at about two to three different places where the grade flattens out for a short distance. The reason the dynamics won't hold the train is track lubrication, we call them greasers which are placed on almost every curve. When in heavy dynamic they will cause wheel slip and loss of dynamics for a short time. If a train takes emergency it will require the train to be secured with hand brakes until the train air is recovered and a set placed back in the train.

Killer views! That second shot is Spectacular!

Depends a lot on the type of train too. Some cars brake better than others. Double-stack articulated intermodal cars are notoriously bad. Coal trains have surprisingly good braking. Grain trains can be a chore because grain dust leaks out the bottom doors and gets on the wheel treads and brakes making them "slippery". Every train handles differently, which is why they've had so much trouble developing algorithms for PTC systems. 80 tons per operative brake is pretty light though. Should be a pretty easy train to handle.

There's another good thread on this here: https://www.trainorders.com/discussion/read.php?1,3358354

I can't help with your technical question but your photos are stunning!

Ditto! Where is that?

SP8595 Wrote:
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> Killer views! That second shot is Spectacular!

Thanks for all your replies! Helped a lot and shows Run8 seems to do it's job quite well

The picture: This is the Tauern railway from Salzburg to Villach (technically from Schwarzach to Villach, check the link: https://en.wikipedia.org/wiki/Tauern_Railway or http://www.openrailwaymap.org/?lang=&lat=46.90512826605979&lon=13.321781158447266&zoom=12&style=standard). This is the south ramp of said route. It is one of the most scenic routes I know but you get used to it after a while ;)

You can check my Flickr for more pictures: https://www.flickr.com/photos/kilux/

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Agree'd AWESOME Shot!

SP8595 Wrote:
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> Killer views! That second shot is Spectacular!

SouthWest RailCams
CA, NM, CO, TX, AZ
https://SouthWestRailCams.com

Nice shots!!

Kilian,
Thanks for sharing some great shots of Austria. That second shot is truly spectacular!

Kent in CArmel Valley

Complements on your command of the English language



Edited 1 time(s). Last edit at 11/23/17 06:33 by Englewood.

Kilian. Great logical thought out questions. First of all I worked Tehachapi for years long before AC units were even designed. The wonderful thing about AC units is on a grade an engineer can release the brakes and put the reverser in reverse ..pull out the throttle to a low setting and pump up the air. If there is a DC unit in the consist is has to be isolated otherwise will damage the traction motor. Most of the time running down the hill with SD 45 s would always have a minimum set applied to balance the grade. My first trip solo over the mountain had a set of the old units. SD 35 , U 33, SD9 s. At Cable my dynamics kicked out and my speed was 25mph. Immediately went to 40 mph in a matter of seconds. Ended up stopping charging the train made a minimum set and pulled the train down the hill at 20 mph. Luckily it was all boxcars and only 2800 tons. The train ID was 365 the Advance Starpacer. One never forgets their first terror trip !
Great photos by the way !

Posted from Android

First, great photos!!


SanJoaquinEngr Wrote:
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> ... One never forgets their first terror trip! ...


LOL, isn't that the absolute truth. Not too long after I started running by myself I had an OAPTT down our hill, Cascade Summit to Oakridge. While I no longer remember the actual tonnage I do remember the lead unit was the SP 9606 (early GP60) with a bad ordered equalizing reservoir / pressure maintaining followed by 2 GP40's; absolute horrible power for our grade. While at 1.8% our grade isn't as steep as other grades, it is the longest continuous grade on the entire SP, even longer than Donner Pass to Roseville (there is a section that flattens out). If that unit were still around today my fingerprints are no doubt still embossed on that brake valve and dynamic brake handle.


In any case, every grade has its own personality and idiosyncrasies so every grade handles differently. Most of our trains could get by with a minimum set but occasionally you'd get one that wouldn't cooperate.



Edited 2 time(s). Last edit at 11/23/17 14:22 by Railbaron.

1ST_OUT Wrote:
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> If I need to stop I
> will use the dynamics to stop the train and hold
> my set.

According to the literature, dynamic brakes in DC motors (i.e. D77) do not provide any braking force below 4 mph (or near). Would the above statement be true if the head end was nothing but SD40-2s?



Edited 1 time(s). Last edit at 11/24/17 07:59 by BCHellman.

While the dynamics won't hold the train we/I would release the brakes but keep the independent applied to hold the train as long as I could. As the train brakes released the train would creep forward so at that point I'd apply sand and start backing off the independent and go to full dynamic. The goal was to get below 15 psi on the independent quickly so the "Independent Pressure Switch" would not be activated and the extended range portion dynamic braking (of units equipped) would start holding the train up around that 4 mph range. This is where experience, good judgment, feel, come into play as you would continue holding the train as slow as possible so you can get a charge (not a full charge) back in the brake pipe. Once you got the charge where you wanted it, or you knew it would be effective, you can come back with a set, hopefully the same reduction as you were using before you stopped.

(SP simulator taught "soft sets / soft brake pipes" and we used that up here but I won't get into that as some people freak out even though there's really nothing wrong if you know how to do it.)

Thanks again for the interesting replies!

Another related question: In the air brake rules (CSX in this case) I found something like before releasing the brakes, you should have made at least a 10 pound reduction. Is this really practical?

"5554 Releasing Train Brakes

A. Running Release

After the desired braking has been accomplished, train brakes may be released, if:
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Brake pipe air is not exhausting.
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You have made at least a 10-PSI brake pipe reduction.
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Brakes on the entire train will be released before the train speed is reduced to 10 MPH."

That 10 psi rule is common on all railroads to my knowledge. The purpose is to insure a good release throughout the train.

Since air brakes apply and release on individual cars using a "signal" received via the brake pipe, a 1.2 to 1.3 pound reduction (apply) or increase (release), the 10 psi reduction prior to making a release insures this pressure change is sensed at each individual car. This rule was much more important with older air brake systems (AB control valves) but since the advent of the ABD control valve, and its variations, this isn't as critical in actual operations.



Edited 1 time(s). Last edit at 11/24/17 08:38 by Railbaron.

A train like that would do great with a minimum service application. Your TPOB tells you everything you need, the old rule of thumb is a pound of air for every 10 TPOB but with modern AC locomotives that rule can be overkill on certain trains. So a train on the low end of TPOB like in the 30s will squat with a minimum and will need a soft set. A train on the high end like in the 120s may need 10+lbs. In the real world the curves on Tehachapi play a part on bringing a train down the hill, a longer train or a train with long cars will bind in the curves and not require as much air or dynamics to hold the train.

In your scenario of Summit-Ilmon, an engineer would be at 25mph by Tehachapi crossovers and at mp359.5 by rule will have the train speed 5mph below the downhill speed so on most trains that is 18mph. That is just a head end restriction so once your headend is by you can increase your speed back up to 23mph. Now you will watch your dynamic brake effort and DPU Comm, this area used to be a bad spot for communication loss and you gotta watch making a set when your DPU is in comm loss as it may place the train in emergency. For that reason many engineers will wait till just past Cable Crossover to A) Make the set where you have DPU communication and B) Get a feel for how strong your dynamics are. Another rule of thumb on Tehachapi is to make your set when your amp meter reads 60 klbs.

Now that your set is settling through the train you will slowly decrease dynamic brake effort to maintain speed. If you find yourself dropping below 30klb your train may require either a soft set OR the easy way and just idle your DPUs. If your up above 60klb to maintain speed your train might require another pound or two. A perfect balance train is using between 30-60klb of brake effort to maintain speed. Anything over 60klb you dont have much room for stopping effort and also risk wheel slip over the greasers. Below 30klb you risk your head end running out.

If you have to stop, modern ACs will bring the train practically to a dead stop. Older DC motors will require the assistance of the independent brake as their effort fades at lower speeds below 5mph. Most trains on most spots on Tehachapi will hold fine with the independent applied and the minimum in the train. At Cable a train will creep and you can set more air to hold the train OR with all AC motors you can back into the train to hold it.

To get moving again you just bury your dynos, release the independent and come off your dynos until your train starts to move. If you have a light train you can release your automatic and place the set back in once your brake pipe has charged.

Now approaching Caliente the grade levels out and as your dynamic effort decreases below 30klb you kick your air off. Specifically on Tehachapi trains are relieved of going to 10lbs before releasing your brakes as this creates a wave throughout the train and can cause your empties to sit down and risk stringlining your train in the curve.

Any other questions about Tehachapi feel free to PM me.

love the variety in your pics!

Someone told me;

Actually in that type of territory you use Air Brakes and Dynamic to balance the grade.  If you are on a 2.2% grade and holding the train back with just dynamos, you are setting yourself up for Mr. Toad's Wild Ride http://bit.ly/1flIpil  if your dynamics suddenly fail.   Now let's say you are dealing with 140 tons per operative brake, like a grain train, and you have a "3 by 4 by 2" batch of locomotives on the train ( 3 on the head end, 4 in Mid-Train and 2 stingers on the rear) you'll probably have enough motors to hold it with strictly Dynamics.  BUT..... If those all suddenly unload (fail) you'll take off down that hill like you were shot out of a cannon.  In a scenario as mentioned above, you'll always want at least First Service set on the Air Brakes which is a 6 to 8 pound brake pipe reduction depending on the brake valve on your locomotive that day and how worn out or worn in the physical automatic Brake Valve is, which will have a fair amount of braking power and prevent a "Cannon Shot" instant acceleration if the dynamics just quit. I've been on trains a couple of time where the dynos just quit working for no reason at all......  If you were sleepy, you weren't after that!   Name Withheld , a retired Engineer here in Place Withheld hired out on the NWP.  One day back when he was a brakeman, he was on the head end southbound out of Willits.  They had 4 SD-9s up front and four more manned helpers 2/3rds back in the train, all lumber loads.  As they were descending Ridge Hill 3+%, the engineer had everything all set up and settled down with the dynamics and air under the train, going about 18 MPH.  He said that the dynos suddenly failed and that old head instantly plugged it.  They got up to something like 35 MPH almost instantly but then the air finally took hold and they got it stopped.  You talk about loading up your pants!  The bad part on that old power was if you went in the "bighole" for any reason, the PCS opened and you lost your dynamic too......   On modern power, you never lose your dynamic brake if you have an Undesired Emergency Brake Application.   He had to tie down a zillion hand brakes, they recovered their air, and the engineer got the dynamics reset and they went on their merry way with the rest of the trip being uneventful.

I'll forward your questions to him. 

ʎɹɹɐl