http://www.sadek-trading.com/ar/modules/mylinks/viewcat.php?...

http://www.fotosearch.com/photos-images/semi-truck.html



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Note added at 1 hr (2007-10-03 04:31:31 GMT)
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towing engine is part of the semi-truck, referring to the engine designed for towing. if a engine is designed for racing, we call it race engine.



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Note added at 1 hr (2007-10-03 04:42:05 GMT)
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http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDispla...
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here are some engines

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Note added at 2 hrs (2007-10-03 05:11:58 GMT)
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Trackaxle
Trackaxle is a re-design of the rear axle set on a semi trailer causing the back end of the trailer to steer itself along a path similar to the prime mover. The prime mover is the front end of the truck consisting of the towing engine, where the driver is seated.
http://www.abc.net.au/tv/newinventors/txt/s1431219.htm
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about the towing engine

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Note added at 3 hrs (2007-10-03 06:04:00 GMT)
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راس قاطر بمحورين ونصف مقطورة بثلاثة محاور
semi-truck with two axels and semi-trailer with three axels
{--O--O--}----{--O----O----O---} that truck will look like this. the one in the front is semi-truck with two axels, the one at the back is the semi-trailer with 3 axels.
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سيارة شحن بمحورين
truck with two axels

the first one on the list, is a small truck without a trailer. it looks like this {---O-----O---}

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قاطرة بمحورين ومقطورة بمحورين
tractor with two axels and trailer with two = a truck
this second one on the list, is a medium truck
{--O--O------O----------O---}

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راس قاطر بمحورين ونصف مقطورة بثلاثة محاور
semi-truck with two axels and semi-trailer with three axels
{---O--O---}{----O----O-----O-----}
{semi-truck}{semi-trailer }

the third one is a huuuuuge truck, in Australia, if the semi-trailer has so many wheels to make it look like a train, then they call it " Road train" too, it is so long that it looks like a train on the road!
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the three types of trucks mentioned on that list: 1. light truck 2. medium truck 3. heavy truck


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Note added at 3 hrs (2007-10-03 06:11:14 GMT)
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if you see a semi-truck on the road like this
{--O--O--}{----O-O----O-----O-----O-----O-O-----}

in Arabic, we can say:
راس قاطر بمحورين ونصف مقطورة بسبعة محاور
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شكرا للجميع...لقد استفدت منكم كثيرا



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Note added at 3 hrs (2007-10-03 06:19:26 GMT)
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tractor with two axels and trailer with two = a truck
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there is a typing error, the right one should be
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tractor with two axels and trailer with two axels = a truck

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Note added at 8 hrs (2007-10-03 11:02:15 GMT) Post-grading
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{--O------O--O---}~~~{--O--O---O--}
{medium truck}~~~{ trailer}

just saw another example on the road, a medium truck towing a trailer ( pls note: it is trailer with 3 axels, not semi-trailer )

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Note added at 8 hrs (2007-10-03 11:11:32 GMT) Post-grading
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more examples:
Example A
{---O-------O-O-----}{---O--------------O---}
{semi-truck with 3 axles}{semi-trailer with 2 axles}

Example B
{---O------O--O----}~~~{----O-----O----}
{medium truck with 3 axles}~~~{ trailer with two axles}


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Note added at 8 hrs (2007-10-03 11:29:09 GMT) Post-grading
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A semi-trailer is a trailer without a front axle
looks like this: {---i-------------O---O----}
http://en.wikipedia.org/wiki/Image:Presenningstrailer.JPG