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Cork roadbed too high? Not by my measurements.

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  • Member since
    March 2002
  • From: Milwaukee WI (Fox Point)
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Cork roadbed too high? Not by my measurements.
Posted by dknelson on Monday, July 28, 2003 8:21 AM
Metromike posted an item saying that he measured his cork roadbed and found it was nearly 3 feet high -- in his opinion way too high.
Other posters were surprised at the 3 feet.
I got out my General dial calipers calibrated to HO scale -- you can measure to fractions of an inch. I measured IBL, Midwest and Atlas cork roadbed and learned -- they don't agree on what constitutes 1/4" but in scale height they varied from 1'4 3/4" (Atlas) to 1' 5 3/4" (IBL). So roughly one foot five inches.
I imagine each manufacturer has variances in production runs.

Just for fun I also measured my 1/2 inch homaote subroadbed and it came out to 3 feet 4 1/2 inches.

And yes Woodland Scenics foam is less. A brand of upson board roadbed and some wooden roadbed was more -- and it also claimed to be 1/4 inch!

So how does that compare to the prototype? I dug out the Pennsylvania Railroad's 1917 standards for double track.
They show stone ballast to 1/2 inch below the top of the tie. Then 23 1/8 inches of stone. Then a subroadbed of 12 inches of cinders. So you are looking at something around 2 feet of ballast -- and something over 3 feet to the bottom of the subroadbed. And then remember you might have further earthworks under that. And even below that you have the drainage ditches on either side, or at least on one side with culverts. So if you think of the bottom of that drainage ditch as being "ground zero" -- meaning the flat surface of your benchwork -- the combination of cork and homasote is by no means too tall, at least not as I figure it. In some cases it might not be tall enough.
Dave Nelson
  • Member since
    March 2002
  • From: Milwaukee WI (Fox Point)
  • 11,435 posts
Cork roadbed too high? Not by my measurements.
Posted by dknelson on Monday, July 28, 2003 8:21 AM
Metromike posted an item saying that he measured his cork roadbed and found it was nearly 3 feet high -- in his opinion way too high.
Other posters were surprised at the 3 feet.
I got out my General dial calipers calibrated to HO scale -- you can measure to fractions of an inch. I measured IBL, Midwest and Atlas cork roadbed and learned -- they don't agree on what constitutes 1/4" but in scale height they varied from 1'4 3/4" (Atlas) to 1' 5 3/4" (IBL). So roughly one foot five inches.
I imagine each manufacturer has variances in production runs.

Just for fun I also measured my 1/2 inch homaote subroadbed and it came out to 3 feet 4 1/2 inches.

And yes Woodland Scenics foam is less. A brand of upson board roadbed and some wooden roadbed was more -- and it also claimed to be 1/4 inch!

So how does that compare to the prototype? I dug out the Pennsylvania Railroad's 1917 standards for double track.
They show stone ballast to 1/2 inch below the top of the tie. Then 23 1/8 inches of stone. Then a subroadbed of 12 inches of cinders. So you are looking at something around 2 feet of ballast -- and something over 3 feet to the bottom of the subroadbed. And then remember you might have further earthworks under that. And even below that you have the drainage ditches on either side, or at least on one side with culverts. So if you think of the bottom of that drainage ditch as being "ground zero" -- meaning the flat surface of your benchwork -- the combination of cork and homasote is by no means too tall, at least not as I figure it. In some cases it might not be tall enough.
Dave Nelson
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Monday, July 28, 2003 9:46 AM
The truth is I dont know what brand it is. It was just in a brown box on the floor of the hobby shop.
  • Member since
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Posted by Anonymous on Monday, July 28, 2003 9:46 AM
The truth is I dont know what brand it is. It was just in a brown box on the floor of the hobby shop.
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Monday, July 28, 2003 1:48 PM
I don't know where you got your calipers, but HO is 1/87 scale, so 1 inch is 87 inches. So 1/4 inch is close to 22 inches which is 1 foot 10 inches, not 1 foot 4 inches. And 1/2 inch is 43.5 inches which is 3 feet 7.5 inches, not 3 feet 4.5 inches. Drop your calipers?
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Posted by Anonymous on Monday, July 28, 2003 1:48 PM
I don't know where you got your calipers, but HO is 1/87 scale, so 1 inch is 87 inches. So 1/4 inch is close to 22 inches which is 1 foot 10 inches, not 1 foot 4 inches. And 1/2 inch is 43.5 inches which is 3 feet 7.5 inches, not 3 feet 4.5 inches. Drop your calipers?
  • Member since
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  • From: Milwaukee WI (Fox Point)
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Posted by dknelson on Wednesday, July 30, 2003 8:20 AM
No didn't drop the calipers. Maybe 1/4 inch is not 1/4 inch --- buy any 2x4s lately?
Dave
  • Member since
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  • From: Milwaukee WI (Fox Point)
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Posted by dknelson on Wednesday, July 30, 2003 8:20 AM
No didn't drop the calipers. Maybe 1/4 inch is not 1/4 inch --- buy any 2x4s lately?
Dave
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Posted by Anonymous on Wednesday, July 30, 2003 9:38 AM
A 2X4 is and has always been 2" by 4". A dimensional 2X4 is what I think you are referring to and is a sawed 2X4 that has been smoothed to an industry and government approved standard size and finish. I measured some Atlas cork with a micrometer and it was .241 inch which is 20.9 inches using the significant digit rules. I am sure there is tolerance and variations between brands and batches, and I would imagine cork roadbed drys out and shrinks, but homasote is a dense manmade material and should be really closer to 1/2 inch than your results show.
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Posted by Anonymous on Wednesday, July 30, 2003 9:38 AM
A 2X4 is and has always been 2" by 4". A dimensional 2X4 is what I think you are referring to and is a sawed 2X4 that has been smoothed to an industry and government approved standard size and finish. I measured some Atlas cork with a micrometer and it was .241 inch which is 20.9 inches using the significant digit rules. I am sure there is tolerance and variations between brands and batches, and I would imagine cork roadbed drys out and shrinks, but homasote is a dense manmade material and should be really closer to 1/2 inch than your results show.
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Posted by Anonymous on Wednesday, July 30, 2003 10:42 AM
"...homasote is a dense manmade material and should be really closer to 1/2 inch than your results show"
Homasote also expands/contracts quite a bit with humidity.
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Posted by Anonymous on Wednesday, July 30, 2003 10:42 AM
"...homasote is a dense manmade material and should be really closer to 1/2 inch than your results show"
Homasote also expands/contracts quite a bit with humidity.
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Posted by Anonymous on Wednesday, July 30, 2003 12:06 PM
"Homasote also expands/contracts quite a bit with humidity." I have always found it expands but never goes all the way back to it's original size. They also make it in 15/32 and 7/16; maybe that's what was measured.
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Posted by Anonymous on Wednesday, July 30, 2003 12:06 PM
"Homasote also expands/contracts quite a bit with humidity." I have always found it expands but never goes all the way back to it's original size. They also make it in 15/32 and 7/16; maybe that's what was measured.
  • Member since
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  • From: Milwaukee WI (Fox Point)
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Posted by dknelson on Monday, August 4, 2003 8:08 AM
My bad! My bad! While my old Atlas rubber roadbed and very old cork roadbed is 1/4 inch high, the new standard is now 3/16", or 5mm, and that is what IBL and Midwest both are -- as is Faller and Busch although I have never seen their roadbed. And they are not misrepresenting anything either -- their ads or packaging say 5mm. It was I who falsely assumed they intended to match the old Atlas height of 1/4 inch.

AMI -- the sticky rubbery stuff -- says it is 1/8 inch. Woodland Scenics foam measures out to something a bit less than 3/16" at least as I measure it (but it is so spongy that it is hard to tell). This is actually useful because it gives a way to have passing sidings or spurs be a bit lower than the main, which is prototypical.

Ribbonrail makes an Upson Board roadbed that is very close to 1/4 inch but just a hair less. And Northeastern Scale Lumber's wooden roadbed (that interlocks in an interesting way) is exact 1/4" so in that sense we have three practical choices for height.

My main point was that between prototype ballast and prototype roadbed fill, the commerical products are by no means too tall
Oh and I remeasured my homasote -- billed as 1/2 inch. Some of it is close to 1/2 inch but some of it is 7/16" So again the combination of homasote plus cork roadbed does a reasonable job of making "ground zero" -- the top of the benchwork -- about where it should be for the bottom of the trackside drainage ditches.
Of course in some places drainage is not the issue -- this may be a regional thing.
Anyway the posters who challenged my caliper reading had a point but it was not the caliper or my reading that left something to be desired -- it was my flat statement that these roadbeds are all 1/4 inch or intend to be.
Moral: measure twice, cut once. Measure twice -- post once!
Dave Nelson
  • Member since
    March 2002
  • From: Milwaukee WI (Fox Point)
  • 11,435 posts
Posted by dknelson on Monday, August 4, 2003 8:08 AM
My bad! My bad! While my old Atlas rubber roadbed and very old cork roadbed is 1/4 inch high, the new standard is now 3/16", or 5mm, and that is what IBL and Midwest both are -- as is Faller and Busch although I have never seen their roadbed. And they are not misrepresenting anything either -- their ads or packaging say 5mm. It was I who falsely assumed they intended to match the old Atlas height of 1/4 inch.

AMI -- the sticky rubbery stuff -- says it is 1/8 inch. Woodland Scenics foam measures out to something a bit less than 3/16" at least as I measure it (but it is so spongy that it is hard to tell). This is actually useful because it gives a way to have passing sidings or spurs be a bit lower than the main, which is prototypical.

Ribbonrail makes an Upson Board roadbed that is very close to 1/4 inch but just a hair less. And Northeastern Scale Lumber's wooden roadbed (that interlocks in an interesting way) is exact 1/4" so in that sense we have three practical choices for height.

My main point was that between prototype ballast and prototype roadbed fill, the commerical products are by no means too tall
Oh and I remeasured my homasote -- billed as 1/2 inch. Some of it is close to 1/2 inch but some of it is 7/16" So again the combination of homasote plus cork roadbed does a reasonable job of making "ground zero" -- the top of the benchwork -- about where it should be for the bottom of the trackside drainage ditches.
Of course in some places drainage is not the issue -- this may be a regional thing.
Anyway the posters who challenged my caliper reading had a point but it was not the caliper or my reading that left something to be desired -- it was my flat statement that these roadbeds are all 1/4 inch or intend to be.
Moral: measure twice, cut once. Measure twice -- post once!
Dave Nelson
  • Member since
    September 2002
  • 7,477 posts
Posted by ndbprr on Tuesday, August 5, 2003 2:27 PM
I prefer something lower then cork so I buy a cheap sheet of paneling and rip it into 1" strips for HO. Then I take about 25 of them and stack them on edge and slot the pieces on a radial arm saw so they will bend on curves. This yields 47 eight foot long pieces from a sheet of paneling or 376 linear feet. this is a lot cheaper than cork and looks better to my eye. not everything that is prototypical looks the best in scale. 8-10 car passenger trains come to mind. at 1/8" thick it is just about 1' high in HO
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Posted by ndbprr on Tuesday, August 5, 2003 2:27 PM
I prefer something lower then cork so I buy a cheap sheet of paneling and rip it into 1" strips for HO. Then I take about 25 of them and stack them on edge and slot the pieces on a radial arm saw so they will bend on curves. This yields 47 eight foot long pieces from a sheet of paneling or 376 linear feet. this is a lot cheaper than cork and looks better to my eye. not everything that is prototypical looks the best in scale. 8-10 car passenger trains come to mind. at 1/8" thick it is just about 1' high in HO
  • Member since
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  • From: Milwaukee WI (Fox Point)
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Posted by dknelson on Tuesday, August 5, 2003 9:12 PM
If I understand you correctly ndbprr you are creating "spline" roadbed a time honored method that creates almost natural easement curves.
Dave Nelson
  • Member since
    March 2002
  • From: Milwaukee WI (Fox Point)
  • 11,435 posts
Posted by dknelson on Tuesday, August 5, 2003 9:12 PM
If I understand you correctly ndbprr you are creating "spline" roadbed a time honored method that creates almost natural easement curves.
Dave Nelson
  • Member since
    September 2002
  • 7,477 posts
Posted by ndbprr on Monday, August 11, 2003 2:54 PM
No, not really. Splined roadbed would have the splines installed vertically with spacer blocks between them. I cut the slots in the paneling so it can be bent on curves. When I am done it kind of looks like a big comb as I cut the slots about 7/8" deep. I lay it flat over a sheet of homasote to just elevate the track a little. You don't need to slot the pieces that will be used for straight areas which saves some work.
  • Member since
    September 2002
  • 7,477 posts
Posted by ndbprr on Monday, August 11, 2003 2:54 PM
No, not really. Splined roadbed would have the splines installed vertically with spacer blocks between them. I cut the slots in the paneling so it can be bent on curves. When I am done it kind of looks like a big comb as I cut the slots about 7/8" deep. I lay it flat over a sheet of homasote to just elevate the track a little. You don't need to slot the pieces that will be used for straight areas which saves some work.
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Wednesday, August 13, 2003 6:40 PM
I don't use cork roadbed in yards or sidings. All my track is code 100 flex which is either caulked or spiked down. I have found building yards on 1x12" boards on the bench is quite easy and yeilds 5 tracks per board and this leaves enough room for fingers between tracks. Ballast is glued to the boards which have been prepainted earth brown. The best way to learn how to put track down and ballast is to go get an 8' length of 1x3 and try all the various methodes.
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Wednesday, August 13, 2003 6:40 PM
I don't use cork roadbed in yards or sidings. All my track is code 100 flex which is either caulked or spiked down. I have found building yards on 1x12" boards on the bench is quite easy and yeilds 5 tracks per board and this leaves enough room for fingers between tracks. Ballast is glued to the boards which have been prepainted earth brown. The best way to learn how to put track down and ballast is to go get an 8' length of 1x3 and try all the various methodes.

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