What's the optimum number of cars for a layout?

[jmbjmb]

A lot of interesting ways to consider things.  I look at it two ways.  The first is to use about 30% of  capacity, not counting staging.  I don't count staging because it can be used in so many ways, primarily as a storage area and storage can hold a lot more than operational track.

For a small, primarily switching road, another other method is to consider how many cars are needed to carry out an ops cycle, then add in the cars that are just passing through.   Not all industries, in fact many shouldn't, be switched every day.  Simulating cars that don't move "today" means you need fewer cars.  I admit this method may fall totally apart on larger layouts.

On my layout, I get the following (15 car track capacity and 12 car staging):

a.  30% method:  15 car capacity x 30% = 5

b.  Cycle method:  6 (based on my industries and their shipping/receiving needs in a "day."

 

[cmrproducts]

I used Joe's formulas on my layout shortly after I had it about 80% of the trackwork finished and it figured out that I should be running around 1300 plus cars on the layout.

I now have 1000 cars and found that it was fairly accurate to being right but at times the yards can be pretty empty!

I have since added another 650 sq ft of layout area with the associated increase in track and industries.  So I am really behind in having enough rolling stock to make the system work right.

I am going to have to go back and refigure all of my trackwork and see what it recalculates out to again as I have added over 500 feet of track, staging and industrial sidings in the past 3 years.

As I have added new cars (usually 5 to 10 at a time) I have OPs Sessions to see how the additional rolling stock helps in filling the industries and/or thru trains.  This way I can evaluate the overall performance of the additional cars without throwing too many into the Sessions and then need to take a bunch back off!

Slowly creeping up to the maximum (what ever value that might be) will be far easier on the old wallet! ;-)

BOB H - Clarion, PA

 

gandydancer19

THREE:
One reply gave a link to Joe Fugate's web site where he has a formula of sorts.
http://siskiyou-railfan.net/e107_plugins/content/content.php?content.32.2
This method is rather involved as you have to measure all tracks
etc. Once you have done this, you convert their lengths into the
number of cars they will hold, then perform a not so simple
calculation to determine the total number of cars for the layout.

[wp8thsub]

To some extent any staging based "formula" will depend on how you use staging and your visible yards.  I use "active" staging wherin a staging operator continually re-stages during a session.  Were I to fill my staging to 100% it would swallow about 300 cars, while the layout has just over 300 now.  The way the operation is set up I just barely have enough.

[Alantrains]

Thanks everyone,

Seems like I'm probably about right with 21 cars running on a layout capable of storing 36 so long as I have 2 main line trains running. I'll have to cycle true some of my extra cars.

Now to work out the ratio of Boxcars, gons, reefers, logging cars and tank cars.

cheers

[cuyama]

dehusman

  A good starting point would be about 50% of your staging,  classification yard and industry track capacity.  

In my experience with several operating layouts, Dave's concise advice is spot-on. Start there and adjust if necessary.

Byron

[BroadwayLion]

Depends on your railroad.

The LION has 1000' of mane lion track (and about 30' of yards.)  Presently I am running only four six-car sets, but eventually I will have all eight sets running plus three or four work trains in the yards. Some day I'll buy some more cars and will run up to 12 trains at once. so there are 48 passenger cars on the layout until such a time as I win the MR contest and can buy some more. But mine is a busy main line operation with departures every 5 minutes. Only a real time clock will work on my railroad.

I have to rework the time table for what I am running now, I made one for 576 daily trains, but it will be less now.  Or maybe not.

ROAR

[gandydancer19]

I hold formal operating sessions using a program called Rail Op on my layout.  The layout is in a single car garage and we run our sessions with four operators.

So I went looking for a way to determine how many cars should be on a
layout for good operations. What I found to determine car capacity
for a layout was the following three examples: (There were more, but
I chose these three to test.)
ONE:
50% of industry spots full
67% of yard and interchange tracks full
90% of staging tracks full.

TWO:
Since then, the Ops Sig group on yahoo has been discussing it as
well. A couple of the replies have been for 50% full for yard and
industry spots and almost full to all full for staging.

THREE:
One reply gave a link to Joe Fugate's web site where he has a formula of sorts.
http://siskiyou-railfan.net/e107_plugins/content/content.php?content.32.2
This method is rather involved as you have to measure all tracks
etc. Once you have done this, you convert their lengths into the
number of cars they will hold, then perform a not so simple
calculation to determine the total number of cars for the layout.

So to find out how these systems stacked up against each other, I did
the calculations for my home layout. The number of cars on my layout
should be: (based on a 40 foot car length)
System 1- 139 cars
System 2- 116 cars
System 3- 156 cars

Of the three systems, number 3 seemed to be the most accurate due to
the many measurements and calculations required. However, system 1
or 2 would be the simplest, and the percentage numbers for No.1 could
be adjusted so the results were closer to system 3. My layout
currently has 102 freight cars on it and seems to be operating well,
but at certain times there seems to be a car shortage. I have
thought there could be a few more cars, but I think that if I brought
it up to 156, I may get grid-locked. I can see going to 120 cars.

As for the number of cars used in a session, this would/may translate
into the number of cars in a train, and the number of trains run in a session.

So also, under Joe's system, you can calculate the optimum train
length. This is based on the number and length of all passing
sidings on the layout. The two different types of train length are:
Dispatch Train length; and Passing train length. For my layout, the
Dispatch train length should be 8.5 cars, and for Passing train
length average should be 9 cars. These are exactly the size of the
trains that I run +/- 2-3 cars, and they work well for my layout. So
to me, this seems to back up Joe's figures. (Or maybe Joe's figures
back up the way I am operating my layout.)

You can also calculate the number of trains run in a session, but I
have not gone that far.

[Alantrains]

Thanks everyone else, I'm a slow typist and many replies came in while I was working out my layouts capacity. Some good info in all your replies. I'm off to bed now. Hope you all have an awesome 2012

[Alantrains]

Thanks TA462,

My layout is 11' by 7' and is a single track oval with 2 station areas, each with a double ended passing track. There is also a switchback branch line. The layout has 9 single ended siding tracks that can hold a total of 28 cars. Plus I have 2 staging tracks that can hold a 4 car train each. So if everything is full I can have 32 cars on the layout before I add a train running around or on the branch line.  A mainline train is usually 4 cars and due to the switchback, branch line trains are only 2 cars and a bobber caboose. Currently there are 21 cars on the layout and it seems to work Ok with a single operator (me) running 2 or 3 trains (DCC). One running around the main line, one slowly climbing the branch and me switching cars in the yard of the bigger station. I am going to add a loco depot with perhaps some passenger car storage for 2 trains later on. I must get a scale drawing of the track done one day soon.

cheers

[james saunders]

Hello Alan,

Probably the best way to calculate it is...

1 - how many industries do you have

2 - how many cars/wagons is the capacity for each industry taking into account in/out loadings

3 - how many through trains do you operate if any

4 - how much staging/ yard track do you have?

5 - times your total by 2

I recommend never having your yard capacity over 75% during operation as it clogs the yard and makes it difficult!

the reason is you'll want to swap cars in and out periodically, you may have a 'core' of cars that are always on the layout but if you have some that are not on the layout you can swap them out at your leisure.

 

I have a grain elevator on my layout. I need 20 covered hoppers to run in and out bound loads, but I currently have 40 coverered hoppers. This allows me to also run a unit train through.

I have about 50 boxcars - you can never have too many boxcars.

I have around 5 centrebeam flats and other flat cars, these don't serve any industry on my layout, but they break up the sea of boxcars and grain hoppers on my manifest trains.

Same with tank cars - I do need more though.

I have 16 intermodal flats and autoracks - for my intermodal train, I plan on getting probably another 14 to make two trains.

I am currently purchasing reefers for my fleet. I have a frozen foods packager on the layout. I currently have 8 but will need at least 25.

So that makes about 120 or so freight cars, I can run my layout with this number - but I will probably stop buying large quantities of freight cars when i'm closer to 200. That is what I envisage to be my Optimum number of cars for the layout. I will of course still buy the odd one, but once I reach 200, I won't "need" more, just "want" more.

 

Cheers,

from another Brisbane-ite!

 

[dehusman]

There have been several different formulas offered.    A lot of it depends on your style of operation. 

A good starting point would be about 50% of your staging,  classification yard and industry track capacity.  I have about 100 cars of industry tracks, 145 cars of staging and 85 of yard for a total of 330 cars of standing capacity.  That means I should have about 165 cars on the layout.  I currently have 110 cars on the layout, and I can tell I need more.

When you get over 2/3 of capacity, things will start to bog down because any hiccup in the flow will overload a yard.

[richhotrain]

TA462

I don't think there is any set formulation to go by.   There are so many variables to consider that I think it would be impossible to pick a number UNLESS you had the track plan in front of you.  

I agree with TA462.

It all depends on how big your layout is, how much storage track or classification track or staging track you have on the layout, and how many operators will typically work the layout.

How big is your layout, how many cars do you have, and how many operators do you anticipate?

Rich

[Alantrains]

I'm sure Tony Koestler has covered this in one of his "Operations" articles, but what is the best way to work out how many cars can fit on a layout built for operation. My guess is that it's a percentage of total storage track capacity.

cheers