General Discussion (Model Railroader)

Peter:

80% is the absolute maximum ... 60% is probably more like it for a really fluid op session.

The numbers represent limits. You don't have to do what they say, but it gives you some idea of how far you could pu***he design before you would "break it", if you will.

You could think of it as "stress testing" your design. [;)]

Joe,

I think your 60%(fluid) number is right on. I have used a similar calculation system(not quite the same as yours), and found if I run at 66% Maximum Capacity, that is the 'sweet spot' I am comfortable with.
I do allow 'seasonal' car orders(and the extra cars needed are added). Somehow the car orders get removed, but the cars hang around and I start using a yard track to store extra cars. At least until I bill out an extra east/west train to move them 'in block' to staging for removal from the system. Just picking them out after the 'grain rush' just creates havoc for a couple of operating sessions after the 'purge'. At one time I put an orange yard sale sticky dot on the extra cars and ran jobs in sequence to move the cars 'off-line' Now I put the dot on the car card and instruct the yardmaster to park the car on the track assigned for car storage.
I suspect 80% is workable, but I like running a low key secondary/branch line operation and the 66% number works just fine.

Jim Bernier

I am a sponge, and you guys are the water!
Keep the ideas flowing, because these are great nuggets of info!
Hey Joe, thanks for the thread!

- Ryan

Topic this post: More cool things we can learn from the layout stats

Besides the things discussed in the last post, there are some very useful insights you can learn about your design relating to trains and your layout operation.

NUMBER OF TRAINS: We can divide the number of cars moved by our average train length to arrive at the average number of trains we can expect in a typical operating cycle. Average train length is the smaller of average passing train length or average staging train length.

One operating cycle is defined as running the layout in a realistic manner until the trains you run begin to repeat. Ordinarily this will be one "24 hour" day according to the modeled train schedule.

Depending on your fast clock ratio, the experience of your crew, the reliability of your equipment, the length of a typical run, and the level of detail to which you simulate prototype operating practices, the actual time it takes to complete one cycle could vary from one hour to dozens of hours. Three hours is probably a good typical cycle, however.

DISPATCHING THRESHOLD: Compute as (3 x shortest passing siding + 2 x average passing siding + longest passing siding) / 6.

Two opposing trains of this size or larger will tend to create a dispatching bottleneck because they cannot easily pass each other except at select sidings. If you want to ease the dispatcher's workload, keep the typical train length at or under this size.

If you want the dispatcher to more easily manage longer trains, then lengthen your passing sidings. The best way to increase this threshold is to lengthen your SHORTEST passing sidings first. Of course, you need to keep the length of your staging tracks in sync with passing siding lengths as explained above under the train length stats.

Another less obvious tactic to improve this stat (if your passing sidings are smaller than your staging tracks) is to declare very short passing sidings to be switching runaround tracks only (and thus connecting track instead of passing track), thereby removing them from routine consideration as locations where the dispatcher might arrange meets.

This tactic also has the effect of increasing the number of cars moved since it creates more connecting trackage.

This concludes the series of discussions on layout stats. Now on to other design insights ...

Next topic: Easements and superelevation.

Great topic Joe!
You have enlightened my track planning stage of my layout incredibly. As it stands in the current form of the plan I have two passing sidings (double track sections actually) that are at least 1.5 X the length of my longest staging yard track.

Look forward to the next topic!

Ryan [^][:D][^][:D]

SilverSpike:

Many an old timer on the Layout Design SIG yahoo forum have said that you should get yourself some string and pretend running trains on your track plan. You'll find many of it's shortcomings early if you do that.

The nice thing with the layout analysis stats is they do the same thing, but are far quicker and less awkard than playing with strings on your plan.

By computing the values for your track plan, you are forced to think through many of the issues according to the insights a savvy layout designer will have already considered.

So you kind of get "instant expertise" in track planning by using these formulas.

By the way, all the formulas and more explanation on doing this sort of track plan analysis can be found on my web site at:
http://siskiyou.railfan.net/model/layoutDesign/layout.html

Glad to help out my fellow modelers in any way I can!

Great topic ! Enjoyed all the info, and as I haven't added any yards yet, now I know a lot more. The knowledge is great, but have a simple mind. I like watching trains. Wish I had Big Boys layout, but like my 4 x 8 until benchwork for new is completed.

Tim

Thanks for the tips, Joe!

I have your website saved as one of my favorites. I will review the Layout Design pages again.

Thanks again,

Ryan

This is an informative and enjoyable topic. I think the statistical models also encourage the designer (me) to think about a certain cohesion or balance in the layout's design. Perhaps it should be obvious that passing siding lengths should be somewhat consistent along the line, or that the lengths of staging tracks will effect the length of the trains you can run, but putting it in a formula has made it make more sense to me.
Has anyone run the numbers on any of the layouts in the popular press besides the ones on Joe's site? It would be fun to see how some of them measure up.
Thanks
Peter
conford

I ran some numbers on Rick Rideout's L&N since I'm a big fan of his layout. I don't have the results handy, but I recall it was interesting to see that the layout was clearly designed for 20 car trains.

That was not obvious by reading the article in MR years ago, but it was as plain as the nose on your face by seeing the stats.

It would be interesting to see stats on other well known layouts, or various published track plans. Which is the point of the article on my website, but the way. [:D]

Time to resurrect this forum clinic since several of the recent questions relate to posts on here.

[:D]

Yes, Joe, pleas do. I have been very much enjoying following this clinic and was hoping it would continue.

Ron

Topic this post: Easements and superelevation

The prototype puts easements in between the straight track (called a tangent) and a curve so the straight track slowly "eases" from straight to the radius of the curve. This prevents cars from "jerking" into the curve from the straight track, and makes the journey easier on passengers and freight.

On the model, easements don't matter because the physical forces on the cars do not scale down, so there is little operational benefit from having easements. However, adding easements adds tremendously to the visual authenticity of your track alignment and makes it look more "right" even to the untrained eye.

As to track planning, adding an easement might offset the location of your curve by 1/2" to an inch (in HO, more in the larger scales, less so in the smaller scales). This is not enough difference to even concern yourself with adding easements to your track plan. Even the process of transferring your track plan to the benchwork could introduce this much error.

There are several ways to model easements -- bent stick, curve templates, spline roadbed -- but that's beyond the scope of this discussion. Suffice it to say that if you use spline roadbed like I do, the easements are formed naturally by the roadbed, so I don't even have to worry about how to add them.

The other track alignment topic related to easements that often comes up is "banking" the curves, or superelevation. The prototype superelevates for the reason you expect: it allows you to take a curve at speed and the banking offsets the outward centrifigal force as the car goes around the curve.

Again, on the model, the physical forces do not scale down, so superelevation is unnecessary. However, it's hard to beat the realism of a model train on a realistically superelevated model curve.

The prototype commonly applies a superevlevation transition in the same place as the easement. While the track is easing from straight to curved, the outer rail is also slowly rising to the superelevation angle that will be maintained throughout the curve. And the reverse happens at the other end of the curve in the transition back to the straight tangent.

Modeling superelevation is beyond the scope of this series, but it's worth pointing out a couple of things. Raising the outside rail more than about a scale 6" (1/16" in HO) is plenty. Also, pay attention to superelevation on the main when you have a non-superelevated passing siding. The superelevation actually reduces the distance between the tracks, so you should increase track spacing to compensate.

Otherwise, you might have cars on the superelevated main hitting the tops of cars on the non-superelevated siding (when the siding is on the inside of the curve).

Ask me how I know. [B)]

This completes the topics for this series, however, I'll also entertain direct questions as long as they are layout design related.

Question? can anyone here recommend a good source (book, magazine,website) for setting up one person operations systems for a small layout?

I had in mind a simpler system like a dice roll setup but do not know where to find the info for it? I think a full blown card system might be a bit too much for my tiny layout.

BTW heres my layout if anyone is interested...
http://1stclass.mylargescale.com/vsmith/GarageStudyDOWNSIZEnew%20studyA.pdf

Thanks for any info. Vic

Vic:

Here's a great link:

http://www.gatewaynmra.org/designops.htm

This is an excellent overview of all things operation, includes different options on how to route cars (your question) and a thorough bibliography of further reading.

This link contains some of the best model railroad operation tutorial info of anything I've ever seen, in print or online. Richard Schumacher is to be commended for a top notch piece of work.