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Tiroir : Voie ferrée en impasse.
www.cdgexpress.equipement.gouv.fr/.../CDGExpress_Glossaire....

TRAIL TRACK : Voie en tiroir, tiroir, tiroir de manoeuvre (JLP
http://www.trainweb.org/cssqscanada/LEXIQUE96.html
However I've found nothing that backs up "trail track"

Y ¬ Wye, or turning track. (A place where trains may
reverse direction.)
http://www.tpub.com/content/armytransportation/TR0635/TR0635...

A triangle or wye, in rail terminology, is a triangular shaped arrangement of railway tracks with a switch (point) at each corner. In mainline railroads, this is used at a railway junction, where two railways join, or cross over. It can also be used as a stub for turning railway equipment. By performing the railway equivalent of a three point turn the direction of a locomotive or railway vehicle can be swapped around, leaving it facing the way it came from. STREETCAR TRACKS sometimes have a short triangle or WYE STUBS to TURN THE CAR at the end of the line.
http://en.wikipedia.org/wiki/Wye_(rail)

WYE - A track with three switches and three legs forming a large triangle which enables an entire train to TURN AROUND. Return to TOP . ...
en.mimi.hu/modelrailroad/wye.html

The train had stopped to take on water at Boone, TN early in the afternoon of ... Altapass also was the site of a TURNING WYE used to turn pushers for their ...
appalachianrailroadmodeling.com/crrsteamhelp.html

There is a TURNING WYE at Salinas to turn the railcar. Also permission has been given to charter a train using steam locomotive No. ...
www.internationalsteam.co.uk/trains/ecuador03.htm

The context is quite limited: it seems to have to do with Lyon's underground transportation system (le métro):
see http://www.lyon-en-lignes.org/forum/index.php?topic=7871.150
...rather than shipping. That's why I suggest a "railway related" translation !

"Tiroir" = track extension
"Switch back" = demi tour
... in the field of railway vocabulary.