Solid Wood Products 



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to removal of treated ties from mainline tracks — particularly in oak (fig. 22-58). 

 Some veteran observers of crossties in service conclude that the only way to 

 reduce weathering of the top surface of a tie is to keep it wet continuously, with 

 no opportunity to dry. This would suggest that poorly drained wet ballast might 

 slow weathering of upper tie surfaces. 



The causes for removal vary with species (table 22-2 1 ). After splits, the major 

 causes for removal of treated hardwood mainline crossties are plate cut (fig. 22- 

 59) and decay. Hardwood ties are far more resistant to crushing and shattering 

 than those made of pine, although tie life appears not greatly different (table 22- 

 21). 



Perem (1971) found that in sugar maple (Acer saccharum Marsh.), the major 

 seasoning checks usually form on the broad tie face nearest the pith and extend 

 toward the pith in the planes of the rays. Perem found the most severe checking 

 in ties with the pith about halfway between the broad faces; in such ties, an initial 

 narrow seasoning check, present when installed, creates a plane of weakness 

 along which repeated loading in service develops subsequent splitting. He con- 

 cluded that the risk of splitting in service is least in boxed-heart ties with the pith 

 less than 1 inch from a broad face, whether placed in the track with pith side up 

 or down. No similar data for crossties of southern hardwoods are published. 



Figure 22-58. — Badly split creosoted oak mainline crosstie. 



