Large Scale Central

Long trains on tighter Radius Curves

General Discussion
#1

This past weekend we had some really nice weather. I had my intermodals all weighted down and running good. I decided I would try to run a train with all the cars I have. You can see the configuration in the picture below. It string lined twice on me.

  1. I had two box cars behind the 3 engines. They are not particularly heaving so it wasn’t surprising. I moved them and left the nice heavy tankers in the front.
  2. The intermodals again. They were near the back this time. After picking up the fallen cars, I tried to pull the remaining cars and they would not budge. Turns out one of my tiny hopper cars had its hatch fall open and wedge itself over a turnout.

Answers to one/both of the following questions will help me determine potential pulling capacity.

  1. What is the longest trains you have run on your layouts including track radius and grade? Be as detailed as you wish.
  2. What are some possible issues that cause trains to fall off the tracks when pulling long trains?

I am wondering though what the potential pulling limit would be on my layout. I have included a picture of the current layout. What is the best way, other then running a long train and hoping it doesn’t string line, to determine what my potential safe max capacity is? Note: Bridges are marked with the grey outline. Red pieces are just pieces I had to trim/fudge to get the layout to work with respect to real life.

Some clarifications for my setup.

  1. All cars have metal wheels.
  2. All couplers are USA Train couplers
  3. None of them are body mounted. The only coupler changes made were to remove LGB style and use USA Train style couplers.
  4. Most cars weight 4lbs or more. A few weight less.

Red Baron Railroad 2018-03-12

#2

It would depend on the speed at which you run, how free rolling the cars are, and any “unforeseens”, like the hopper car misbehaving. One of my turns is a teardrop that almost comes back onto itself. The tracks are maybe 10 inches apart where they almost come together, the grade is 2.58%, and the curve is about 10 foot diameter. I have run my F3, or RS3, with enough cars that the engineer can wave to the brakeman in the caboose, as they roll past each other. The only time I have an issue, is when some foreign object finds its way under a car and jams a wheel, or the car. And I use truck mounted couplers.

#3

Pulling power of loco(s)(# of cars each can move). Level of track, size of curves, length of cars, weight of cars, freeness of wheel sets, speed of train, cleanliness of track. All can infringe on your questions answer. Placement of car may/may not effect their tracking ability as this goes back to the individual free rolling ability of each car. Trains don’t put all stack cars together in a mixed freight they sort them according to destination. Tight curves put more resistance on the flanges. Grades effect pulling power and downgrades can get pushing effects from trailing cars.

Place a loco on the tracks with a few cars and run it. Add cars, one at a time, and run your train till it starts to bog down. You have reached it’s ability. If you always run two or three locos lashed together then run your test with that number of locos. Relocate the cars in your consist and run some more. If you always place your cars in a set order you best mark it down because if you change a cars location you may find a problem you didn’t find before.

It is different for every situation and each train at each location. Good luck with the quantum physics if you want a definitive answer.(https://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)

#4

I added some clarifications to my post to clear up. I am not as worried about whether the engine can pull it or not. That is pretty straight forward as either the engine moves, or it slips/doesn’t.

I am primarily concerned with string lining because that means cars go falling and with my current railroad all supported up, they fall 2 to 5 feet depending on where they are.

I would also be curious about what other sort of issues, that would result in cars falling off the tracks to their doom, I should be aware of if I am to try this again.

#5

i don’t see, how we could give you a guaranteed “recipe”.

more generally speaking, when i made this type of “falling-tests”, i found out that it helps, to have the heaviest cars right behind the loco and the lightest at the end of the train.

#6

Staying on topic and have tired to help in the past however I’m clearly not experienced enough with these situations so I must bow down. Would like to watch and learn the key factors with other posts that this thread will hopefully entertain.

#7

If you leave off the longer intermodals is everything fine as long as you don’t have a “hopper drop”?

#8

Nicolas Teeuwen said:

I added some clarifications to my post to clear up. I am not as worried about whether the engine can pull it or not. That is pretty straight forward as either the engine moves, or it slips/doesn’t.

I am primarily concerned with string lining because that means cars go falling and with my current railroad all supported up, they fall 2 to 5 feet depending on where they are.

I would also be curious about what other sort of issues, that would result in cars falling off the tracks to their doom, I should be aware of if I am to try this again.

Sudden changes in speed can cause string-lining in a train that normally would not string-line. Its a matter of what is easier for the locomotive to do, pulling the train through the curve, or pulling it off the rails. So there is no set answer.

Yes, heavier cars should be up front.

If a car has an axle that doesn’t spin freely, then it will drag on the cars ahead of it and can pull them over.

Other issues for cars falling over;

debris on the track

Uneven track, as in track leaning one way when it should be level or leaning the other way (super-elevation)

Excessively large, or uneven gaps between sections of track

Track or wheels out of gauge

Hanging parts catching on switches or other track work (like low coupler pins)

Trucks that don’t swivel freely

Having neither truck on the car free enough to rock a little

Wheels that bind, and don’t spin freely

coupler that doesn’t swing freely

Gust of wind

and in my case, squirrels who think the track is their highway and who bat trains off their track.

And I am sure the list goes on.

That is why elevated track makes me nervous. If my trains topple over, they usually don’t have far to fall.

#9

Rooster thanks Maynard for this useful post

#10

My only comment:

change to all body mounts except perhaps the intermodals.

Truck mount couplers exert twisting forces on the trucks, not good in any situation, horrible with a long train, because the forces become extreme.

Think about what the pulling forces are doing, they are trying to turn the trucks.

I have a 45 car train that goes up a 3.4% grade 60 foot long, levels out makes a hairpin turn 180 degrees and then goes down a 5.5% downgrade and turns at the bottom…

Could never do that with truck mounts…

Greg

#11

Nicolas, your track plan turned out spectacularly. You did a great job smoothing out those awkward crossovers and turn-outs you started out with. If I were to ever get far enough out into my yard, I’d steal this.

#12

Thanks Greg. What type of curves are involved in that section of track you describe?

Most of the USA Trains couplers pivot to a certain degree independent of the truck so I would expect that to max out before the truck itself turns. Its a tiny piece of plastic that provides a spring like action to the coupler. That said, all the 4 bay center flow hoppers have couplers directly on the mount.

Thank you David Maynard for that list of possible things to keep an eye out for.

I prefer not to switch to body mount couplers because.

  1. It would be expensive/time consuming. I don’t plan to run trains extremely long unless I can do so without anything more then regular car maintenance.
  2. With the tighter radius curves I have I was under impression that body mount couplers would be more problematic for the cars going around the curve.

I can definitely run trains that are 20+ cars long without an issue and for now that is likely the most I would typically do. This was more of a curiosity test and an understanding of the various things that could go wrong, resulting in falling rail cars.

Thinking about this situation more I think what I am really looking for are peoples experiences. So to rephrase my questions.

Please share the longest trains you have run on your layouts including track radius and grade. Be as detailed as you wish.

Having a collective thread detailing various configurations that have worked for people will help me, and future railroaders to understand what configurations have been shown to work for others as a starting point for themself.

In my case the longest configuration that has worked on all parts of my layout reliably has

  • 3 engines (GP38 or SD70) with 2 50ft box cars, 4 42 foot tank cars, 11 4 bay center flow hopper cars, 1 50ft box car and 3 single bay short coal cars.
  • All USA Trains cars with USA Trains couplers mounted as is from factory.
  • Smallest curve on level track is 9 ft diameter.
  • Smallest curve on a grade is 10 ft diameter.
  • Steepest grade is in the high 3%.
  • Track is all Aristocraft and USA Trains Brass 322.
#13

Nicolas,

  • Longest trains on outdoor layout without experiencing “string-lining” vary as to car type mix, but generally range from 35 to 40 cars max.
  • All cars have metal wheels.
  • Locos do not have traction tires.
  • Longest train ever run on underhouse portion of layout was about 60 cars, mostly consisting of Aristo 40 foot long box cars.
  • Locos pulling train to outdoor layout typically comprise minimum of 3 but up to 6.
  • Outdoor layout tightest curves are 10 foot diameter at viaduct area, but most are 16 to 20 foot dia.
  • Underhouse layout curves include 10 foot diameter except for some rail yard access is 8 foot dia.
  • The few “S” bends used are separated with a straight track section between their diverging opposite paths.
  • Grades on lower outdoor area double helix average about 2.2 percent with steepest portion at 3 percent section on a 14 foot diameter curve. Grades on upper area are 2.2 to 2.5 percent.
  • Underhouse portion of layout is level, suspended from rafters by threaded rod.
  • Locos and cars (400+) have body mount Kadees “G” centerset type couplers - except USAT SD70s having medium upward offsets (Presently working on replacing these with centersets).
  • Outdoor track is all Aristo-Craft stainless steel connected with Split Jaw brand stainless steel clamps.
  • Underhouse portion of layout is Aristo brass track.
  • Turnouts include Aristo #6, #6 Wye, Wide Radius having 10 foot dia. diverging path, TrainLi R7 plated nickel silver.
  • Track power via Aristo Revolution 15 amp base station with multiple feed 10 AWG wires to outdoor layout.

-Ted

#14

When metal wheels were mentioned, I did not see what type were used.

Here is what I see in metal wheels for weight, rated lightest to heaviest for what I personally own:

Trainli Stainless rims Rim type wheels will always be very light weight

LGB nickel plated brass rim type wheels.

Bachmann cast wheels

USA Trains solid brass, very heavy.

USA train wheel sets are best outdoors for me as it lowers the center of gravity which is very useful for curves and wind bursts.

#15

Nicolas, I run 20’ curves except in one area behind my storage barn. I had to use 10’ do to the distance from it to the fence and I was tired of hauling dirt in that summer, so I shortened the layout.

It does limit the length of my trains. I tried running over 30 cars just a week or so ago and it would streamline in that 10’ section every time. I posted a video of a train running just last week. It had 29 cars on it, well 28 and a caboose. It ran for about an hour then out of nowhwere would streamline. So, I took it down to 25 cars. For me about 22-25 cars seems safe…most days. I prefer to run longer trains though. I know I never have trouble running 20 car trains. So, time permitting, I am hoping to expand this summer.

Everything I have has body mounted kadee couplers. I also notched the coupler box’s to allow more wheel travel. Almost all of the cars have metals wheels. There are a couple that don’t and they will be replaced eventually.

#16

“I have a 45 car train that goes up a 3.4% grade 60 foot long, levels out makes a hairpin turn 180 degrees and then goes down a 5.5% downgrade and turns at the bottom…”

Outer loop that has these grades has a minimum of 9.5’ diameter at the 180 degree hairpin, which then goes into the 5.5% downgrade.

I have avoided grades on a curve, except on the 60 fool long 3.4%, it continues another 25 feet with a couple of gentle curves.

I have run up to 55 car trains of mostly 40 footers and maybe 10 50 footers all centerset Kadee G scale couplers, all metal wheels, all 3-4 pound minimum weight.

I could probably run more, but this is with single headend power, will try with distributed power.

I’ve left the 45 car train running for hours unattended.

Here’s the 45 car train (pretty sure) going up the 3.4% grade and around the hairpin and down the 5.5% grade:

https://www.youtube.com/watch?v=UyH4kd84L3k

Greg

#17

Matt Russell said:

Snip "…I run 20’ curves except in one area behind my storage barn. I had to use 10’ do to the distance from it to the fence…

…It does limit the length of my trains. I tried running over 30 cars just a week or so ago and it would streamline in that 10’ section every time…" Snip

Matt,
Are your curves sizes of 10’, 20’, etc. in radius or diameter?
Did you mean string-line instead of “streamline”? (meaning cars tend to pull in a straight line on the inboard side on curves and off the track)

Thank you,
-Ted

#18

Ted, the big curves are 20’ diameter curves. The small section is 10’ diameter. You are correct, it pulls the cars over to inside of the curve. Normally about 4-5 cars back from the engine, then all the cars on the track inside the curve fall inward.

#19

Ted Doskaris said:

The few “S” bends used are separated with a straight track section between their diverging opposite paths.

That s curve separation is very important in any model RR scale when body mounted couplers are in use.

That being because of their displacement from track centerline and how at an s they displace in opposite directions from cars on the opposing curves of the s.

There is a good length for it and a bad length for straight between s curves.

A good length is a little longer or any amount longer than the longest car expected to be used.

A bad length is anything less than that.

#20

My solution to running long trains - do it D&RGW style (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-laughing.gif)Fastest up front, next fastest in the middle and slowest one in the back. Stops everything getting shunted off in the curves. The major problem I experience, all my stock has body mounted couplers, is when the distance from the bogie pivot to the coupling ends is too great for the radius of the curve and they swing out beyond the extent that the coupling allows and everything gets dragged off. That and knuckle joints and pivots sticking causing the same effect. I’ve got a rake of AMS Fn3 framed tankers that I cannot get to run right