Got A Question....
- Thread starter Iron Goat
- Start date
Re: Got a Question - My Speculation.
Bob,
That trestle is what many loggers would call cribwork and it may be associated with a crib bridge or trestle or it may be a cheap method of taking the railroad over a depression, without the expense of fill work.
I’m just guessing here, but the poles could be to help stabilize the stringers. The poles all seem to be attached to the stringers in this photo. Anyway, that’s my speculation.
Here is a quote on cribwork from Bryant’s 1924 book on logging; I think some might find it interesting, as follows:
“Cribwork. – A crib foundation may be used when logging railroads cross low places that are too soft for a fill, and where the lumber company is not prepared to put in pilings. Logs 18 or 24 inches in diameter and 16 or 18 feet long are placed across the right of way at intervals of 8 feet. On top of these, and parallel to the roadbed, round stringers from 18 to 24 inches in diameter are placed 56 1/2 inches, center to center. These are notched into the cross-skids and drift bolted to them. The crossties are then laid on top of these stringers. The cross skids are given a grater bearing surface by placing “shims” or poles from 4 to 6 inches in diameter and 8 or 10 feet long at right angles under them.”
“Cribbed bents, similar to those shown in Fig 104, are sometimes used on spur lines to span shallow depressions because they can be rapidly constructed at a low labor cost. They are now seldom used when a structure more than a few feet in height is erected because of the large amount of timber required to construct them.”
For narrow gauge of course the stringers would be closer, and I’m sure there are variations to Bryant’s brief description.
In ghost railfanning the Red River Lumber Company’s depression built Piute logging line, I found a cribwork crossing of the Susan River still intact some 50 years after it had been built. It was kind of exciting for me! It was the first and only structure of its type that I’d ever seen other than in photographs.
Jimmy “B”
Reno, NV
Bob,
That trestle is what many loggers would call cribwork and it may be associated with a crib bridge or trestle or it may be a cheap method of taking the railroad over a depression, without the expense of fill work.
I’m just guessing here, but the poles could be to help stabilize the stringers. The poles all seem to be attached to the stringers in this photo. Anyway, that’s my speculation.
Here is a quote on cribwork from Bryant’s 1924 book on logging; I think some might find it interesting, as follows:
“Cribwork. – A crib foundation may be used when logging railroads cross low places that are too soft for a fill, and where the lumber company is not prepared to put in pilings. Logs 18 or 24 inches in diameter and 16 or 18 feet long are placed across the right of way at intervals of 8 feet. On top of these, and parallel to the roadbed, round stringers from 18 to 24 inches in diameter are placed 56 1/2 inches, center to center. These are notched into the cross-skids and drift bolted to them. The crossties are then laid on top of these stringers. The cross skids are given a grater bearing surface by placing “shims” or poles from 4 to 6 inches in diameter and 8 or 10 feet long at right angles under them.”
“Cribbed bents, similar to those shown in Fig 104, are sometimes used on spur lines to span shallow depressions because they can be rapidly constructed at a low labor cost. They are now seldom used when a structure more than a few feet in height is erected because of the large amount of timber required to construct them.”
For narrow gauge of course the stringers would be closer, and I’m sure there are variations to Bryant’s brief description.
In ghost railfanning the Red River Lumber Company’s depression built Piute logging line, I found a cribwork crossing of the Susan River still intact some 50 years after it had been built. It was kind of exciting for me! It was the first and only structure of its type that I’d ever seen other than in photographs.
Jimmy “B”
Reno, NV
Me thinks that this bestest gess that you kan do with that lerned stuff from skool seems ok, love them big enjeneering wurds!
If I was a loco engineer, running over these cribwork trestles, I'd feel much better about doing the job with the BIGGER braces instead of those broom stick sized ones!
Jimmy B
Reno, NV
If I was a loco engineer, running over these cribwork trestles, I'd feel much better about doing the job with the BIGGER braces instead of those broom stick sized ones!
Jimmy B
Reno, NV
JIMMY and MARC,
Thanks guys, you two have really cornered the market for on having the answers to all the logging questions. Thanks much for the information, and Marc's photo helped clarify it even more.
Bob
Thanks guys, you two have really cornered the market for on having the answers to all the logging questions. Thanks much for the information, and Marc's photo helped clarify it even more.
Bob