Selective Compression
#1
A recurring theme that seems to pop up in every thread on an industry or a railroad to model is the difficulty experienced as a modeller attempts to successfully selectively compress the real world prototype into a reasonable scale representation without overwhelming the modeller or the layout.

I have the beginnings of a theory that we should be able to devise a rough rule of thumb to help us with this vexing question. Without resorting to any fancy maths I think that part of the answer may lie in using odd numbers of visual references and orientating streets and buildings, vehicles and tracks in non standard geoetric shapes, ie slightly out of square and parallel. Have you ever noticed that it is harder to count an odd number of items than an even number, particularly when they are randomised in some way?

I am not advocating that we build Wonky World, but that we utilise artistic tricks and techniques to enhance the credibility of our representations of the real world.

A penny for your thoughts.

Mark
Fake It till you Make It, then Fake It some More
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#2
This is something that's been done in model railroading for as long as I can remember. Track not running parallel to the edge of the bench work where practical and/or introducing broad sweeping curves where the track would otherwise be straight; street/road crossings run at an angle to the track; structures (industrial or otherwise) placed at angles to the track; using mirrors to add depth or make a track appear to be longer than it really is; and of course only modeling a portion of a structure; the list goes on.

I've also seen mention of a "rule of thumb" for reducing the size of structures/tracks, but can't recall what it is supposed to be right now. Perhaps if the prototype industry spots 5 cars, then the model can be compressed to spot 3 without losing too much of its character. If a prototype track has the capacity of 20 cars on the prototype, then reduce it to maybe 25% on the layout.

I've planned, at one time or another, to include structures on my switching layout, that even after compressing them end up being 48-60 inches in length. Real space eaters, but they don't overwhelm the entire layout since I have a fair amount of length to work with. If I had less space, then I'd have to look for prototypes that would be what I term "model railroad size". In other words, industries that only spot one or two cars at any one time; and they are out there.

I'm sure open to thoughts or ideas for a simple way to selectively compress track/structures, without the track or structure looking too small to justify rail service.
Ed
"Friends don't let friends build Timesavers"
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#3
My only thought on "selective compression" is:
If there is no room for the full scale size of the building, there is also no room for the full scale size of the surrounding topography.
It all has to be "reduced" to fit, and the reductions should all result in a balanced, "normal" appearance.

The three old modules were "grown". the only planned feature was the two track main, that was part of the original specifications for the individual module.
In the process of "growing them", I had to selectively compress a lot of scenery. It looked good enough from the normal viewing level, but when I finally got a chance to photograph the set from a high vantage point ( Ariel view ), I was surprised to see how lucky I was that it actually came together, and looked somewhat believable.
   

The hard part is in not "overpopulating" the reduced property size. Wink If a scene becomes too crowded?.......selectively compress the number of "added details ".
Kind of like....one dumpster instead of five, or....if the "field" had sixteen old tires lying about, and the "field" had to be reduced 50%, to fit, only use eight old tires lying about.
The feel of the original scene can be maintained, even if the "vastness" of the area has been diminished.
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#4
On small (8' or less) ISL I am beginning to wonder instead of selectively compressing the industries maybe one or two large ones with several spots be better or perhaps one large industry that is either switched by a plant switch engine or a short line that offers switching services to large industries.

Another thought would be 2 or 3 24" industrial flats along the backdrop with a distribution track on front of the layout instead of 4 or 5 tiny buildings?

Maybe we been program to selectively compress instead of getting the best use out of our space?
------------------------------------------
IMHO there is nothing that kills realism faster then a small plant that looks like a 45' trailer would jam the receiving dock.Now park a 50' boxcar there and where's it going to be stored-remember you need a production area.
Larry
Engineman

Summerset Ry

Make Safety your first thought, Not your last!  Safety First!
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#5
My whole layout is "selectively compressed", and if you look at it as a whole, it sometimes doesn't make much logical sense. For example, I wanted a road to connect my town area with my smelter complex. Otherwise, how would my LPBs get from the town to the smelter? Wallbang But the road has to cross 4 tracks of a yard, and realistically, one or more of the crossings will always be blocked Misngth . It's a compromise, but some of my compression was an attempt to fit in interesting elements and create individual scenes. I have enough topography and view blocks to where the non-harmonious elements are not part of the same "scene".
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#6
For modern ISL might be careful selection an alternative to selective compression.
The prototype proportions of modern slab buildings to 60' cars and two GP38-2 doing the switch job are given. The realism will suffer severe if we destroy that proportions on our layout.

ps. I did look at many many video clips on youtube what kind of engine power is used today serving industry. We should accept that two full size engines (minimum length GP15, maximum length Genset) are the standard "switchers" today. That has severe impact on the length of stub tracks to hold the cars to dropped/picked plus the "switcher" doing the job. Youtube has many clips with great examples how BNSF and UP are serving local industry in the LA basin (we should not focus to much on the LAJ because that is more the exception than the norm). Two full size engines are the minimum. The last UPY SW1500 left the LA basin in 2008.... no more excuse for short engines.
Reinhard
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#7
You also don't always need to compress everything - you can leave stuff off entirely. For example - model the spur that leads to the industry, but not the industry itself.

Kevin - I don't think your scene is a compromise - although you don't have to illustrate that there is a road - it might be unmodelled. However, there is a prototype for everything. The town I grew up in had a sizable CPR yard with 7 tracks that crossed the Townline Road. There was quite a bit of hold-up, but not completely unmanagable. Wink


Andrew
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#8
Mr Fixit Wrote:we should be able to devise a rough rule of thumb to help us with this vexing question.

Byron Henderson has posted quite a few well articulated thoughts on compression in various forms on his blog:

"Selective compression" vs "compressive selection" - http://mrsvc.blogspot.com/2009/04/select...ssion.html
"Caricature, copy or close enough": http://mrsvc.blogspot.com/2009/06/carica...nough.html
"Perils of the prototype" (as part of the tricky traps of design series): http://mrsvc.blogspot.com/2006/11/tricky-traps-5-8.html
"Track plan analysis" - part 2 about train capacity, flow and balance: http://mrsvc.blogspot.com/2008/02/track-...dexed.html

As for rules of the thumb - it depends on what you are modeling and what scale you are in. Compression rules of the thumb are very likely different for a display layout vs a dispatching layout vs a switching layout (to use three rough descriptive terms), or for an N scale layout vs an H0 scale layout.

For a H0 scale switching layout in a bedroom sized layout, a train length of 7-8 cars often work well - and could be said to represent maybe a 30-40 train (which rhymes with the 25% figure posted above). It gives a train that is about half a wall length long, which gives you room to have a couple of train lengths between sidings.

But for an N scale passenger train rolling through the landscape, it is not a given that 4 passenger cars will give you same feel as a 16 passenger car real train. There I would guess that you would need to go to e.g. an 8 or 10 car passenger train.

For a H0 scale switching layout, handling cuts of 3 or more cars is often sufficient to give the impression of the train handling cuts of cars - as opposed to handling one or two cars. For a H0 scale switching layout, an industry often has a respectable size if it has 3 or more car spots.

What it comes down to in the end is to maintain flow and balance. Not putting together trains that will stretch through several scenes at the same time, not make trains so long that they cannot fit into sidings etc.

Another approach - more suitable for a dispatching style layout - where traffic flow is important - was taken by Roy Dorn, who formulated a set of formulas to calculate how many and how long trains a given track plan could afford (at the most). Joe Fugate has the formulas on his web page - here: http://siskiyou-railfan.net/e107_plugins...content.32

I once ran the calculations on a track plan just to see what the calculations said - they sorta made sense in that context:
[Image: double06.jpg]

Room area : 6.5 x 11.5 feet = 74 square feet
Layout area : 44 square feet (59% of room area)
Number turnouts : 30


Mainline track: 48 feet (96 cars)
Passing tracks: 11.3 feet (22 cars)
Roseville siding : 6 feet (12 cars)
Yard track 1(A/D): 5.3 feet (10 cars)
Staging tracks: 12.6 feet (25 cars)
Service tracks: 0
Storage tracks: 33.9 feet (67 cars)
Yard tracks 2-6: 18.1 feet (36 cars)
Industry sidings: 15.8 feet (31 cars)
Connecting tracks: 24' (48 cars)
Switches: 264cm (12 switches not already counted as part of main line x22cm)
Yard lead: 118 cm
Flour mill runaround: 2 feet
Other connecting track: 294 cm


Passing sidings: 2
Passing train length: 12 (max)/11 (avg)/10 (min) cars
Staging tracks: 2
Staging train length: 13 (max)/12 (avg)/ 11 (min) cars

Maximum number of cars: 105*0.8 = 82 cars
storage: 67
staging: 25
passing/2: 11
Number of cars moved: 124 * 0.4 = 50 cars
staging: 25*2 = 50
passing: 26
connecting: 48
Average train length: 11 cars (avg passing)
Trains: #cars moved (50) / avg train length (11) = 5 trains (really just under 5)
Dispatching threshold: (3x10 +2x11 +12)/6 = 10 car trains

Nuff random thoughts on the subject for the evening?

Grin,
Stein
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#9
This is an interesting discussion! Stein, I am impressed by the amount of work you put into it. I enjoyed Byron Henderson's blog entries. For me the acceptability of any selective compression seems a subjective perception. I'm sure a lot of modelers would say that my LaRoche Manufacturing company stretches the limits of believability with its size being only a little larger than the freight car serving it, but I like it . Smile

[Image: IMG_2072.jpg]

Maybe its position in the back of a scene makes it less obviously undersized. I'm thinking the principle of "Good Enough" probably applies for most viewers of selectively compressed models.

Ralph
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#10
But for an N scale passenger train rolling through the landscape, it is not a given that 4 passenger cars will give you same feel as a 16 passenger car real train. There I would guess that you would need to go to e.g. an 8 or 10 car passenger train.
Stein
----------------------------
Actually a N Scale 16 car passenger train would fit the layout you drew.

Your yard tracks would hold 60-70 N Scale cars-18' is a lot of yard capacity in N seeing 1 50' HO boxcar is almost 2 N Scale 50' boxcar in length.

Looking at N Scale there is less "Selective compression" or "compressive selection" especially on the Godzilla size N Scale layouts.

Think of this.Even a N Scale 6' ISL is a lot of switching when properly planned-the industries can be a size bigger by using the backdrop instead of stand alones.
Larry
Engineman

Summerset Ry

Make Safety your first thought, Not your last!  Safety First!
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#11
Brakie Wrote:Looking at N Scale there is less "Selective compression" or "compressive selection" especially on the Godzilla size N Scale layouts.

As I already pointed out - how much you would need to compress depends on the modeling scale and your goals for the layout. It is very obvious that going to smaller scales allows you, in the same space, to either model a scene with less compression, or to more scenes, to put more distance between modeled scenes.

But in N scale, a mile (5280 feet) is still fairly long - 33 feet instead of the 60 feet it would have been in H0 scale. Distance track center to track center for tangent (straight) track is 1 3/16" instead of 2", so in theory - in 24" of depth, you could have 10 parallel tracks in H0 scale and 18 parallel tracks in N scale, still leaving room at the aisle for a small safety zone and at the back for a building flat.

I would submit that both "compressive selection" (selecting smaller scenes to model, instead of trying to model e.g. huge yards) and "selective compression" (representing something by a shorter variant, using fewer tracks etc) are still significant factors to both to people modeling in N scale and to people modeling in H0 scale.

As for the 16 car passenger train (of 80-foot cars). In N scale is about 8 1/2 - 9 feet long (depending on how many engines you want at the front), needing 9 - 9 1/2 foot sidings, staging tracks etc.

Whether it would have been sensible to do a 9 foot train instead of e.g. a 4 1/2 foot train (i.e. 16 cars instead of 8 cars) in a room that is 6.5 x 11.5 feet depends on what your goal would have been - just watching a long train roll by, or having room for several sidings and a train length or two between each siding.

Design is (IMO - YMMV) above all an exercise in tradeoffs and finding a balance. There is a large element of personal judgement here - it is not necessarily sensible to set up a simple formula and just say : in H0 scale we reduce train lengths to 25% of the prototype, while we in N scale reduce train lengths to e.g. 45% of the original (to compensate for N scale allowing objects being 1.8 - 160/87.1 times longer in the same room length).

One of the points made in Byron Henderson's article on "caricature, copy or close enough" - trying to be totally faithful to the prototype at all times doesn't necessarily always result in a good design.

Smile,
Stein
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#12
Ralph Wrote:This is an interesting discussion! Stein, I am impressed by the amount of work you put into it.

Oh, not much work - I just copied and pasted from a couple of previous discussions elsewhere :-)


Ralph Wrote:For me the acceptability of any selective compression seems a subjective perception.

I agree. And the compression ratio does not have to be the same all along a layout. An extremely common thing in layouts (so common that most of us doesn't even think consciously about it) is e.g. that the distance between towns/modeled scenes often is compressed a lot more than the distances within the town/scene.

Or as Byron Henderson describes a specific design challenge when modeling a town: "On a project I am completing now, one of the challenges is a scene that was about half of a mile long in real life. It needs to fit in about 600 scale feet of benchwork between two curves. While a simple 4-to-1 compression would theoretically fit, it wouldn’t capture the personality of the signature elements, which include a truly massive industry, a very modelgenic station, and a couple of smaller typical Midwestern rail-served businesses.

Fitting it all in while including a bit of the street grid that helped define the real scene required flipping one spur to point west instead of east and placing a station on a curve. This allowed the track configurations around the large plant to more strongly resemble their real life counterparts.
"


Ralph Wrote:I'm sure a lot of modelers would say that my LaRoche Manufacturing company stretches the limits of believability with its size being only a little larger than the freight car serving it, but I like it . Smile

[Image: IMG_2072.jpg]

Maybe its position in the back of a scene makes it less obviously undersized.

Putting stuff at the back of a scene often allows you to make them look bigger - the brain is "fooled" into (or rather - finds it less jarring) to think that we are only seeing part of the structure - there is more somewhere behind it.

For this specific building, FWIW, I think that the combination of seeing the large silos (belonging to another industry) in the background, having lots of track, the obviously cramped space between the track and the rocks behind it and having an road with a truck there makes me think that this is a small receiving/shipping building shoehorned into a narrow spot on the railroad - where the industry will be loading or unloading single boxcars, and then transport them by truck to their actual production facility, and not the actual production facility.

Smile,
Stein
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#13
faraway Wrote:For modern ISL might be careful selection an alternative to selective compression.
The prototype proportions of modern slab buildings to 60' cars and two GP38-2 doing the switch job are given. The realism will suffer severe if we destroy that proportions on our layout.

ps. I did look at many many video clips on youtube what kind of engine power is used today serving industry. We should accept that two full size engines (minimum length GP15, maximum length Genset) are the standard "switchers" today. That has severe impact on the length of stub tracks to hold the cars to dropped/picked plus the "switcher" doing the job. Youtube has many clips with great examples how BNSF and UP are serving local industry in the LA basin (we should not focus to much on the LAJ because that is more the exception than the norm). Two full size engines are the minimum. The last UPY SW1500 left the LA basin in 2008.... no more excuse for short engines.

...... assuming all buildings have the very same size. But even if they had, we should accept that giving the impression the building is modelled to scale, is what we are after. Lot of neat little tricks, e.g. selective compressinon, could do a lot.
Choosing the modelled spot cleverly, like era and locale, compressed selection, makes it easier to fit a scene in. I would think i could date back my layout to 2007 and still be modern, even modelling LA basin.
Paul
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#14
Paul, it is not my intention to backdate the layout to get a desired effect. I am thinking about the given proportions today. May be I am somewhat alone because I am a fan of the Genset and have to deal with the problems resulting from those long switcher consists.

My conclusion is to make structures that contain loading docks not shorter than 2' to maintain realistic proportions of a large building to a significant smaller cut of cars (possible with attached switchers). I think 2' is a dramatic compression compared to most modern slab buildings with loading docks.

Two examples (both backdated to 199x but in the mean time updated to the present tense )
[Image: IMG_1071.jpg?t=1318965545]
[Image: IMG_1065.jpg?t=1318965536]

ps. The UPY SW1500 did not run alone prior to 2008. It was mostly used as the third engine... not really helpful on a small layout :o The frequent use of CCRCL (old B23-7 and B30-7 as remote control devices) by UP makes things even more dramatic.
Reinhard
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#15
Wow, I kicked off quite a topical discussion when I opened this can of worms and thank you for your contibutions so far as a focussed discussion topic such as this can be a great resource without being too layout specific.

Plenty to read and ponder.

Mark

IMO In My Opinion?
YMMV ????? I couldnt decipher this one.
and there was one other, FWIW, has got me beat.
Fake It till you Make It, then Fake It some More
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