>>In article <33C76D81.270ED190@progsoc.uts.edu.au>, Cam
>><"cam[NoSpam]"@progsoc.uts.edu.au> writes...
>>>> Yes the overhead [for the new Sydney Australia LRT line] does appear
>>>> to be for normal pantograph operation,
>>>> > however what is different is that; double contact wire has been hung.
>>>> I would be interested to know why this is done, too. The new tramway
>>>> system at Sheffield UK uses this kind of double-contact wire, as do some
>>>> of the new French tramway systems, ie Rouen. The contact wire used seems
>>>> thicker than the single wire used on most tramway systems.
>There is another reason for using twin contact wire. Using two wires
>effectively doubles the conducting area, thus reducing voltage drop under
>heavy current. Therefore, the use of twin contact wires in Sydney may be more
>to do with using only one substation rather than two, which might otherwise be
>required.
Yup. Added feeders can be provided, crossbonded as needbe, both
positive and return. However adding a second CONTACT wire, adds
complexity, mass and expense to the OHL. Simple feeders will do as well
to add contact area. Dual contact wires add dual contact...
thanks
dave pierson |the facts, as accurately as i can manage,
Digital Equipment Corporation |the opinions, my own.
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Shrewbury, Mass USA pierson@gone.enet.dec.com
"He has read everything, and, to his credit, written nothing." A J Raffles