The BNML

For me, the answer is "BOTH!"

• Prototype Schematic - BNML
• BNML Track Plan

Track plan

Phil

Spend most of your effort on the key elements that you like and want that convey the flavor you want. After that compress parts of the railroad track plan to connect the key elements together.
 

Also 'Both'

Select LDEs important to the scene then track arrangement to accommodate yet still resemble the actual in appearance, function, sequence, etc. Models are different from real so some deviations are needed to get a good operating model that also conveys time and place - a balance of compromises. Exact 1:1 track plans may or may not (more often) make good model track plans. 

It depends

Are you familiar with the concept of an LDE (Layout Design Element)?  If not, it's basically a key scene or location which needs to be included in a layout.  Think of it like a bead, and the remainder of the layout is the thread which connects the beads together.

In my opinion, it all depends on what you expect out of your layout.  If you're a railfan who's visited certain key locations on the prototype and nothing in between, then all you will need is to connect LDEs with some generic (for the era and locale) scenery and track.  On the other hand, if you're intimately familiar with every inch of track on the prototype, then in a sense the entire layout becomes one large LDE, and you will have a tougher time.

In general, I like to first pick out those locations which are critical to the feel and operation of the prototype.  Those get compressed as much as practical without losing the original purpose.  I then try to connect them with main line which has as much in common with the prototype as possible.  That means putting curves, roads, bridges, etc. in the same relative order if possible.  Thus, in a sense, the entire railroad has been distilled, but the less important parts less so than the remainder.

Prototype compression

Excellent points Ken.  I completely agree.

Personally, I think if you're modeling a specific prototype and you're familiar with that prototype's operations, and if you'd like to replicate them on your layout, prototype compression becomes kind of a given.  When I first got interested in the IAIS, I was fine with just getting close on the track schematic, but the more I railfanned it and got to know the specific work each job did, the more I wanted to recreate those exact moves in my basement.

"When designing a new track

        It depends on how much room you have and how much layout you want to build. The less room or the smaller they layout desired the more compression and distillation will be required. The minimum required would be one typical interesting part or signature scene of the line with everything else imagined to be off scene.  Most people have room for more than one scene or station so they pick some more that are typical and then link them together in a hopefully enhancing  manner. Personally if it comes to compressing locations to the point that they are visually unrecognizable I'll usually leave out some stations to allow the remaining ones to  look more realistic. If the space is too small and layout operating goals are too big I'd rather  just freelance something to fit than model something in a manner that doesn't capture it's appearance or feeling.....DaveB

Thank you everyone for your

Thank you everyone for your thoughts and how each person  tackles it. What is coming  through is  using  LDE  to pick  key elements of what your trying to model.

So when people see it they can relate to the area your modeling.

Agree with Joe and Ken

I'm in the design / build stage of my shelfie (yes, I'm one of those heathens that designs while he builds) and I'm finding as I lay out potential track arrangements that it's much easier for me to leave out scenic elements or an industry spur than main tracks.  I'm specifically modeling the CN (ex-EJE) Leithton Sub from Normantown MP16.1 south to about MP 10 in Plainfield and it just doesn't look "real" without the two mains and the return to single track in Plainfield.  Of course it'll be compressed since I don't have space for 10 scale miles of track.

I'm pretty close to the BNSF (ex-BN) triple track and I ride METRA on that weekdays, but there's no way I could do a reasonable 3 track main in my space in HO.  Dropping to 2 tracks would look weird IMO.   Same for the UP (ex-CNW) a bit farther north.