Author Topic: Question About Ladders  (Read 1264 times)

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Caveman

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Question About Ladders
« on: January 14, 2017, 03:13:10 AM »
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Can someone tell me what I'm doing wrong here? I'm obviously not understanding something.

Using SCARM with the Kato Unitrack library, I laid out some example ladders to compare: a straight ladder, a split ladder, and a compound ladder. (The 90 degree crossings on each end are just to make sure I have the tracks perfectly aligned for comparison purposes.) I wanted to compare pinwheel ladders too, but I couldn't work out the geometry with Unitrack.

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Using the "Length of the Selected Section..." function I measured the red portions of the tracks layouts. From top to bottom I got these values:

Straight Ladder
4.25”
13.93”
23.52”
33.10”
42.68”
52.29”
169.77” Total

Split Ladder
23.14”
32.76”
42.37”
42.68”
33.10”
23.48”
197.53” Total

Compound Ladder
42.37”
32.73”
23.33”
13.68”
14.24”
4.67”
131.02” Total

The two halves are mirror images of each other, so I thought they would make valid comparisons. I must not be understanding compound ladders although I tried copying from photos I found on the Internet. The compound ladder has the least amount of space by quite a bit.

I only measured the length of the straight track (in red) as sometimes I have trouble coupling cars on curves.

What am I doing wrong or not understanding?

Thanks,
Chuck




wcfn100

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Re: Question About Ladders
« Reply #1 on: January 14, 2017, 03:32:11 AM »
+1
You missing one turnout off the the first one that goes to the outside of the ladder.



Jason

Caveman

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Re: Question About Ladders
« Reply #2 on: January 14, 2017, 03:39:50 AM »
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Thanks. Back to the drawing board.

Caveman

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Re: Question About Ladders
« Reply #3 on: January 14, 2017, 04:20:02 AM »
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I redrew the compound ladder and it made quite a difference. These are the new measurements.

Compound Ladder
42.37”
32.73”
33.10”
23.48”
24.48”
14.68”
15.83”
186.85” Total

17.08” Difference

@wcfn100 — Thanks again.

jagged ben

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Re: Question About Ladders
« Reply #4 on: January 14, 2017, 11:09:56 AM »
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Your new compound ladder has seven tracks as compared to six for the examples.  However it should still come out a wee bit ahead of the straight ladder if you removed the extra track.

Thanks for giving us a good demonstration of the differences.

wcfn100

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Re: Question About Ladders
« Reply #5 on: January 14, 2017, 11:31:59 AM »
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Your new compound ladder has seven tracks as compared to six for the examples.  However it should still come out a wee bit ahead of the straight ladder if you removed the extra track.


Part of the reason for a compound ladder is to get the extra track when compared to a straight ladder. 


Jason

Cajonpassfan

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Re: Question About Ladders
« Reply #6 on: January 15, 2017, 08:23:42 PM »
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This isn't Kato unitrack, but the idea is the same. Compound ladders allow for more uniform track lengths, I this case my 14 track Barstow staging yard.
Otto K.

jagged ben

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Re: Question About Ladders
« Reply #7 on: January 15, 2017, 10:08:49 PM »
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Part of the reason for a compound ladder is to get the extra track when compared to a straight ladder. 

Jason

Fair point, but then an apples-to-apples comparison would also have the extra track for the split ladder.   And I sort of assumed Chuck had a six-track yard in mind.  Just wanted to make sure it wasn't missed.

wcfn100

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Re: Question About Ladders
« Reply #8 on: January 15, 2017, 10:13:42 PM »
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Fair point, but then an apples-to-apples comparison would also have the extra track for the split ladder.   And I sort of assumed Chuck had a six-track yard in mind.  Just wanted to make sure it wasn't missed.

No worries, I almost pointed out the same thing but decided to wait to see if he said anything about.  As for the split ladder, I thought about that too, but those don't really operate like a traditional yard, so I I didn't know what to say.

Jason

tehachapifan

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Re: Question About Ladders
« Reply #9 on: January 15, 2017, 11:10:48 PM »
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Amazing what that one compound ladder turnout adds in track space. Seems like a no-brainer but is easily overlooked.
Russ

C855B

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Re: Question About Ladders
« Reply #10 on: January 15, 2017, 11:43:37 PM »
+1
Amazing what that one compound ladder turnout adds in track space. Seems like a no-brainer but is easily overlooked.

It may be overlooked since outside of automated hump yards, compound ladders are somewhat uncommon in the prototype. To hand-throw a switch, you have to cross tracks, and then cross back, making for safety issues - the potential for trip-and-fall around active tracks being #1. Split ladders have a similar hazard - crossing an active track - but in most 1:1 situations with split ladders, there are separate crews working each side. Anyway, conventional ladders leave all the throws on the outside, with no need to cross tracks to throw a switch.

Also, the percentage of real estate taken by ladders in a prototype yard is small, so the gain with compounding isn't going to make that big a difference. It's the compression of modeling that makes compound ladders a useful tool.
...mike

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We don't make mistakes, we have happy accidents. We just don't tell anybody. -Bob Ross

tehachapifan

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Re: Question About Ladders
« Reply #11 on: January 16, 2017, 12:25:38 AM »
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Good points, Mike. Yeah, I guess the real world is not quite as space starved as most layouts and would not typically need the compound laddering.
Russ

wcfn100

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Re: Question About Ladders
« Reply #12 on: January 16, 2017, 02:42:13 AM »
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It's the compression of modeling that makes compound ladders a useful tool.

I'd say it's the use of fixed track components that make a compound ladder most useful.  The prototype has many other options for optimizing space in a yard.

Jason

Caveman

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Re: Question About Ladders
« Reply #13 on: January 23, 2017, 04:15:40 PM »
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Thanks everyone for your responses. Here is an updated image where they all have seven tracks for a better comparison.