How to figure layout capacity?

[BroadwayLion]

PRR8259

Uh, you might want to check before you say BNSF has no sidings 3 miles long. I've read that they actually have built sidings 17,000 feet in length, etc. in the Powder River Basin.

 

No matter, they need those sidings across the entire system to make longer trains a possibility.

The alternative is to double track the system.

 

[PRR8259]

Uh, you might want to check before you say BNSF has no sidings 3 miles long.  I've read that they actually have built sidings 17,000 feet in length, etc. in the Powder River Basin.  

In the model world, I had a decent length passing siding, but the Kato #8 turnouts did not do well with dcc.  I removed one of the Kato turnouts, thus converting the passing siding into a stub track siding, and now my trains are running better in dcc.

John

[BroadwayLion]

Dayliner

I'm trying to figure out the maximum number of freight cars I can have on my layout before I clog up the works completely.  I seem to remember that a good rule of thumb is 75% of your actual capacity, based on total capacity of staging tracks, storage tracks, yard tracks and industrial spots, but excluding tracks reserved for passenger or service equipment as well as passing sidings or any other running tracks.  Any comments or recommendations?

 

 

The length of your passisng sidings.

BNSF would hafe no trouble running trains two or three milew long, but they have no passing sidings that long.

[PRR8259]

My layout was designed to allow me to railfan my own trains.  The total siding capacity is approximately 30 cars.  The shelves above the layout can easily take another 40 cars.  I view my capacity as being 30 cars on the layout itself.  At that point my mainline is clear, so I can run a single unit (if needed to break one in) or a caboose hop.

Sometimes we run 50 and 60 car trains because my son wants to do that, but I try to only leave 40 or so on the layout when I'm not home to run it...10 on the mainline (for son to do whatever he pleases with).

John

[riogrande5761]

Build in lots of layout storage / staging!  That's my advice.

[cefinkjr]

cuyama

 

A couple of points. While Joe has popularized the layout analysis concept, the major themes come from an article by Dr. Roy Dohn from Model Railroader magazine, June 1968. (as Joe acknowledges)

Thank you for the citation (in bold above).  Although I've enjoyed most of the replies, that's really what I was looking for in the first place.

I've printed those three pages (pp46-48) and will be refreshing my faulty memory.

Thanks again.

[BRAKIE]

rclanger

But someone who is modeling the modern era would have 85 foot cars.

Actually modern freight cars ranges from 42' to 89' and the trap is designing a layout that can hold 70-80% capacity and its not as easy as it sounds because general service boxcars can average 50-60'.Gons ranges from 50-65 feet.The average reefer today is 63' up from their once common 57'.Tank cars vary in length as well.

Even designing a ISL for modern operation calls for careful planning and car selection.

 

[rclanger]

I could not help but notice that no one has mentioned the car length. A "car" is not a unit of measure. So Wayne, who I believe models the 40's era, might use a 40 foot car as his standard unit of measure. But someone who is modeling the modern era would have 85 foot cars.

That is for freight operations. If you add heavy passenger operations or just one passenger train the maximum car length would change. So the OP who has not started aquiring his cars must take era and freight vs passenger operations into account.

[tomikawaTT]

Caveat:  I have a LOT of hidden staging, and no problem getting the specific train I want to appear in the visible world at its timetable-appointed hour (minute, second.)

For the JNR portion of my railroad, the capacity is the capacity of my staging tracks - period.  The operating portion of the system has a small yard (capacity 40 4-wheel wagons) and a few spurs with a total capacity of about twelve.  One normal local is enough to max the spurs, and two through freights would choke the yard.

My coal-hauling short line runs point-to-point, and meshes with the far end of a loads-out, empties in arrangement via a train elevator.  At any given instant, there are three (of a total four) unit trains hidden in the netherworld.  Other cars occupy about 40 percent of total trackage.  That fourth unit train is in motion, stopping only for an engine change (shortline steam to JNR catenary, or vice versa.)  I could add a few more cars, but prefer not to.  The empty tracks are typical of a laid-back operation that doesn't move much except for those coal units.

Even though I have JNR staging for eight through freights, eight local freights and all of my passenger consists (each passenger consist has its own dedicated track) I have also provided for rapid transfer of local freight size cuts (12 cars) to and from cassettes for off-layout storage.  Eight cassettes (full and empty) are racked on dedicated shelves.  One is a special design, intended to aid in unloading open-topped cars.  The others are simply `rain gutters' of steel stud, with flex track caulked to their bottoms.

I seriously doubt that I will ever overload the layout.  I don't expect to add that many cars to my roster.

Chuck (Modeling Central Japan in September, 1964)

[doctorwayne]

The capacity of any layout will vary according to both the layout design and the operational plan. 
My layout, for instance, is a point-to-point-to-point, with staging at all three endpoints, plus an interchange with staging.  Cars come from storage to staging, work their way around the layout in one manner or another, then are returned to storage.  I have no modelled yards - these are represented by the combination of storage and staging.  The only on-layout storage capacity is in industrial sidings and that is usually determined not by the siding length, but by the ability of the industries to load or unload cars.   Since I consider staging to be part of operations and not part of the layout, its capacity is not figured into the equation - the only requirement for operation then is that an empty track be available for the next arriving train.  The staging yards can be full only if there is no train scheduled to arrive there before at least one train departs.
Because I operate alone and use DC, trains are run sequentially:  there may be several trains on-line, but only one is running at any given time.  Therefore, passing sidings may be considered only as temporary storage areas while another train passes by.  In most cases, the passing siding is used while the loco of the train in it switches that particular town.  If there is a through train, travelling from one staging area to another, with no intermediate stops for switching duties, the capacity of the layout is determined by the number and length of the passing sidings,  but, in practice, at least one of them has to be empty so that the next train arriving can use it while switching that particular town. 

I did a quick on-layout calculation of siding capacity on my layout - there's a partial second level yet to be built, with additional siding capacity and staging and interchange to be added - that wasn't included.  A quick count shows just over 350 freight cars available  (passenger and non-revenue equipment wasn't included) and, on the existing layout, room for about 190 cars in industrial sidings.  However, the total number of cars normally in those sidings would likely be closer to about 80 cars.  Some of the siding length is available for car storage, if needed, but isn't actually used other than for access to the industry.  Of course, not all industries would use all of their useful siding length all of the time, either - the capacity is there when I decide that it's needed, based on operational requirements.
Passing sidings in all four of the so-far modelled towns will each hold a 10 or 12 car train, so with three of them in use at any given time and one other similar length train in-transit, there should be 120-130 cars on the layout proper.   If, when all of the layout is operational, this number needs to be adjusted, it will be done through revised operations:  shorter or longer trains, and/or ones run more- or less-frequently.

Wayne

[cuyama]

Dayliner

Quite a range of opinion--Joe Fugate's 80% seems quite high to me

A couple of points. While Joe has popularized the layout analysis concept, the major themes come from an article by Dr. Roy Dohn from Model Railroader magazine, June 1968. (as Joe acknowledges)

Second, Dr. Dohn's 80% figure is only for storage, staging (and oddly) passing tracks. It's not for the layout overall, and especially not for yards. [Note that Joe himself has far less than 80% of his total potential capacity on his own layout]

Finally, the best advice is to start operating with the cars you have -- don't worry about how many you will eventually need. The amount you buy will exceed the amount you need for operating -- that's just the way it works out. So buy only a few at a time and continue operating. After you've had some number of operating sessions you will have a better feel for how many and what types of cars are needed to suit your specific layout.

[Burlington Northern #24]

try operating at what half of your guestimated number of on layout cars is. I added a dead end interchange just so I could get cars on and off the layout. 

[BRAKIE]

My rule of thumb is simple..

On my ISL I vary the number of inbound cars as well as the pickups as long as the layout isn't "walbash" with cars..

[Dayliner]

Thanks guys--helpful responses here.  Quite a range of opinion--Joe Fugate's 80% seems quite high to me, while I am surprised that some suggest going as low as 50%.  The concept and theme of the layout are pretty clear (regional shortline running 5-7 trains a day in a "hub-and-spoke" operation).  Staging and passing tracks are designed to support 10-car trains.  Not a lot of long, heavy through freight operation.

The good news is that I do not yet have all the rolling stock I will eventually need--part of the reason for asking this question now is to help me plan future acquisitions to fit the operating plan so I don't go over the top in car purchases (but I know--there will be some "must have" purchases that just don't fit the plan!).  Shelves are always a good idea.

[cuyama]

Most folks find that 50% or less occupancy of yard tracks is better for free-flow of traffic. Staging tracks can be pretty full, as long as you have room for the first moves of your operating "session".

Much depends on how you use the layout, its theme and concept, and how the layout is designed. A one-size-fits-all rule of thumb won't be accurate in most situations, but the 75% number you mention for active visible trackage such as yards is probably too high in most cases.

Many layouts I see would be better off if they stored some of the excess off the layout on shelves or in drawers, rotating cars on-and-off. When the layout becomes a storage solution, ops suffer.

[John Busby]

Hi Dayliner

The rule of thumb sounds about right, but I would include passenger stock in the mix other wise the switcher won't be able to make up and break up the trains in the coach yard before they are taken to the terminal.

Also don't include yard arrival and departure roads in your equation either the real railroads try and keep these roads clear except for exactly what the name says they do.

But put train shelves up its almost inevitable you will end up with too much for the layout.

regards John

[wmshay06]

The ROT I've read and used for years is 50% of spurs, storage and yard tracks - as it pertains to freight traffic.   Staging tracks are not included in this per se. I know Tony Koester (sp?) has advocated 2N+1 on staging tracks - where N is the number of trains expected. However, I think that might depend upon how they will be used.  My experience operating on my own RRs in the past is that much above 50% can effectively shut down a RR from a operational standpoint - there's just not enough flexibility to get jobs done without a lot of frustraion. 

If I was to recommend anything is to target 50% and then (maybe) carefully add in a few cars at a time to see what happens.  You could find that there is a 'happy medium' above 50% that will work for you.

Charles

[jguess733]

Try this link, it might have what you are looking for.  http://www.siskiyou-railfan.net/e107_plugins/content/content.php?content.32

[Dayliner]

I'm trying to figure out the maximum number of freight cars I can have on my layout before I clog up the works completely.  I seem to remember that a good rule of thumb is 75% of your actual capacity, based on total capacity of staging tracks, storage tracks, yard tracks and industrial spots, but excluding tracks reserved for passenger or service equipment as well as passing sidings or any other running tracks.  Any comments or recommendations?