英語版 traction Traction traction tractive traction traction traction traction en:Traction (engineering) en.wikipedia.org traction traction English 英語版 English Traction (engineering) traction traction traction טרעקשאן English traction force traction force equation tractive traction http://en.wikipedia.org/wiki/Traction_%28engineering%29 traction traction traction Traction (engineering) traction traction http://en.wikipedia.org/wiki/Traction_%28engineering%29 English traction