"Kummler and Matter overhead is also widely used in Wellington.
It was
installed (by crews sent out from K&M in Switzerland) throughout
the
downtown area in the early 1980s, as part of the general revamp
of the
trolleybus system. It has since been installed on suburban sections
when
renewals become due, particularly on curves. Because of this process,
K&M
overhead is now mixed with older overhead designs, making for
a fascinating
experience for overhead aficionados like myself. On the short
Aro St branch,
where I live, there is within about 1 km some K&M overhead,
some of it
suspended from bracket arms, some Ohio Brass, a few old BICC hangers
and
quite a lot of locally manufactured stuff copying OB designs.
The Wellington experience with K&M switches has not been
so positive. The
original downtown installation included a large number of switches,
most of
which have now been replaced by local variants of the OB design,
or removed
as part of overhead simplification. The K&M switches are very
complex and
quite delicate and seemed unable to cope with the mechanical stresses
here.
(Peter may want to comment about the influence of local driver
habits!) For
a time it was common to see an overhead crew struggling to rebuild
a switch
as etb traffic banked up and twisted copper runners lay in the
gutter.
The K&M switches were originally supplied with little white
light signals
suspended beside the switch. They indicated the direction the
switch was set
in, but were of no use to the driver, who could not see them at
the crucial
time because of their location. They were soon removed. Are they
used
overseas at all?"
So the failure of the K&M switches was due to a complex
and fragile design
which could not stand up to the mechanical rigours of daily operation,
at
least in this city. When the K&M facing switches were in operation
I do not
recall that they could be used any faster than the old OB designs
- but
perhaps the drivers had become cautious through experience!
By Derek Cheung
Most of the switches in San Francisco are controlled by the
Fahslabend
induction switch control system, and most switches are set for
the
"straight through" direction of travel. Pavement markings
indicate to the
driver exactly when he/she should be/should not be signalling
to activate
the switch. They also use pavement markings to show where the
"dead spots"
in the overhead are.
Vancouver doesn't use K&M special work nor Fahslabend switch
control, but
we do have pavement markings to indicate which direction "power
on" takes
at power on/power off switches. These markings also indicate to
the driver
exactly when to "power on"...
by Brent Efford
I hope I didn't give the impression that Wellington had found
K&M overall to
be a failure - only the special work, which failed due to its
fragility. The
curve and tangent design appears to be very successful, to the
extent that a
lot of suburban curve work has been retrofitted with the K&M
flexible
suspension system, replacing rigid OB style curve segments. My
impression is
that vehicle speeds around these curves can be higher, and operation
is
certainly smoother and quieter.
One slight downside I have witnessed with the flexible K&M
tangent
construction is that a rough dewirement can propagate a sine wave
ripple
along the trolley wire for several blocks, violent enough to throw
off the
poles of other trolleybuses on the section. Rigid suspension would
damp out
such shaking of the wire in 2 or 3 spans. On the other hand, dewirements
are
much less common now.
It is interesting to note how much OB and K&M style components
are mixed and
matched in Wellington. There are OB span insulators supporting
the K&M
pendulum wires, K&M nylon span hangers supporting OB ears,
steel span wires
supporting K&M insulators supporting OB ears and so on. The
lines
maintenance people must have overcome the problem of differing
screw thread
standards somehow.
Wellington also uses pavement markings to indicate how switches
should be
operated. In our case the marking is a yellow bar at right angles
to the
direction of travel, with "on" and "off" underneath,
according to the
direction to be taken. There are also markings, consisting of
a rectangle
with a diagonal stripe, to indicate where to power off for section
isolators. Are these pavement markings similar to those in Vancouver,
San
Francisco etc? Or does each city do its own thing?
by Jim Holland
San Francisco uses a filled-in-circle of yellow for *each*
breaker and as a
rule there are two breakers (insulators) at every switch. Where
two directions come
together or diverge, a tail is used to indicate the direction
of the breakers.
We don't have any more of the power switches - just selectric
and induction.
Markers are not needed for selectric and a simple circle is used
for induction.
Wayside lights indicate the setting of the switch and while perfectly
visible to the
operator/driver, the bulbs themselves are usually burned out.
Couldn't dropping
resistors help this problem? Or a voltage rating for the bulbs
about 10% higher than
the operating voltage!
I believe that the K&M intersections on the 1 California
are going to be
replaced with standard Ohio Brass type construction within the
next couple years, at
least this is what the overhead crews are indicating. I have
*not* seen this in any
of Muni's planning manuals, long or short range.
My biggest beef with modern day trolley coach overhead construction
is that
they place the curves so far to the inside of the curve that there
is no room for a
coach to use its maneuverability - it is essentially like a streetcar,
stuck on a
fixed guideway. The only room to maneuver is move to the inside
of the turn but the
coach would be so far out of alignment that it would either be
completely on the
sidewalk or COMPLETELY in the lane of opposing traffic. And while
there may be an
*element* of benefit to this design in that the poles are travelling
slower than the
coach to decrease dewirements, stretching the poles to the max
through overhead
special work is a formula for disaster - I absolutely do NOT respect
this type of
construction.
I first noticed this with the K&M construction for the
1 Cal and thought it
odd, but it proliferates with recent construction and has caused
some MAJOR headaches.
For the coaches returning to the Presidio garage from the 5 Fulton
or 21 Hayes, their
turn from Turk to Masonic is a prime example. This is a left
turn with a dedicated
left turn lane and the wires are to the left of the double yellow
line divider BEFORE
the first crosswalk. A coach CANNOT pull directly into the intersection
to preempt a
left turn when traffic clears resulting in many near miss accidents.
Many drivers did
not realize the wires were so far to the left when the new wires
were first used and
when they were making *normal turns* the poles would not reach
the wires. This
happened for months. And this is *just one of MANY* similar types
of turns!
Another very bad feature of overhead construction is in the
hardware known as
a mechanical crossover. It is officially known as the "Type
SM Mechanical Crossovers"
and Catalog #s 22441 for 10 degrees and 22442 for 15 degrees by
Ohio Brass. This is
for the shallow crossing of two wires and contains points to carry
the shoe through.
They are normally set in a neutral position but the shoe entering
the crossing sets
the points to align for the right direction supposing preventing
the crossing from
acting like a switch and causing the trolley to take the wrong
wire, but I have seen
that happen MANY times. These crossings seem to freeze up rather
than operate
properly making it sound like a trolley has hit a brick wall and
usually causing a
dewirement. The overhead crews say they have more trouble with
this crossing hardware
than anything else they deal with. These crews also indicate
that they get generic
products from a number of different sources. That MIGHT be part
of the problem.