Doctor Drivel wrote:

"Rod" wrote in message
...

Also remember that repairs to a diesel bus happen in a garage and
inconvenience few, the repairs to the power lines for trolley buses
cause disruption to lots.. a factor seldom taken into account.

The lines are also on the sides of buildings too. This creates problems
in itself for building maintenance and when some drop down - or
teenagers pull them down.

Has this ever happened? Teenagers pulling them down, I mean.

Some years ago I heard about use of flywheels for buses. Thought
struck me then - marry a trolley bus with a flywheel and/or batteries.

o The complex junctions which were a rats nest of overhead cables
would not be needed. This would dramatically reduce installation and
maintenance overheads (sic :-) ).

o Any problem on the road (accident, roadworks) could be driven round
in a way not possible with pure overhead.

o There would have to be a clever re-connect-the-pickup-to-the-wire
mechanism. So you wouldn't need a chap with a long wooden pole at the
terminus of each route.

There is a new ground pickup point for street trams. It is about 1 foot
beneath the surface and is only energised when the tram is rolling over
the rails. It is completely safe, so they say, so kids can't get fried,
and used/being tested on the Continent.

It is in service in Bordeaux. Previously the conduit system has been
used (London, and various other places in other countries) to avoid
overhead lines. The modern system is similar in principle to the stud
contact system used occasionally in the early years of tram operation,
though that system was not very succesful, as studs often did not
de-energise after trams passed. The Bordeaux system seems to work as
intended.

There are also tram/trains, used in Germany (Karlsru?) and being tested
in Yorkshire. These run fast on conventional rails and then onto slow
streets.

Karlsruhe was first, several more have started in Germany and in other
places since.

Trams are light rail (slower), trains are heavy rail (faster).
Underground trains are heavy rail. There are also duel fuel trains,
(electric pickups overhead or 3rd rail) and diesel.

The terms "light rail" and "heavy rail" as they are so often applied
inconsistently. In Europe "light rail" tends to mean technologically
descended from trams rather than heavy rail vehicles, but if you compare
something like a 3 (articulated) car DLR train to a tube train, you
won't find that much difference between them in terms of speed,
passenger capacity, weight and so on.

Trams are not a great thing. Manchester, Sheffield and Croydon adopted
them and only Manchester is successful.

Croydon manages 24 million passengers/year on 18.5 route miles compared
with 19 million on 23 miles for Manchester. Somewhat shorter in length,
Nottingham manages 9.7 million on 9 route miles. Sheffield, often
regarded as the poor relation of Manchester and Croydon manages 13
million on 18 miles, which isn't too bad. Of course "successful" is an
entirely subjective term.

They shake adjacent buildings

The pertinent question is whether they shake the buildings more or less
than the alternatives. One tram can replace 3 buses, or about a hundred
cars.

and the overhead lines are ugly.

If they are really a problem, adopt the Bordeaux solution. Personally,
I don't find them too bad, especially if care is taken with the supports
(the Nottingham approach rather than the Croydon one).

Robin