Transposition Brackets

[NW Mailing List]

In the days of the telegraph and telephone, both the ACL and the Norfolk
Southern had transposition brackets on the cross-arms of lineside telegraph
and telephone lines.  If two wires stay parallel for a certain distance they
have a tendency  to induce each other's signal. To prevent this possibility
there are transposition brackets placed at strategic cross-arms. This
bracket has one insulator located above the cross-arm, and another
insulator positioned below the cross-arm to take the two wires  temporarily
out of being parallel for a short distance, thus preventing line induction
between the two lines.  Did the N&W use these devices?   Or more to the
point,  are there any of them left on today's lineside cross-arms?  I know
that they were used widely by AT&T and regional telephone companies.
Bill Sellers
Gainesville,Ga.