For Bath, the use of standard overhead trolley wire with an electrical supply at the continental standard of 750 volts D.C.is proposed. The old Board of Trade Regulations specified a minimum height of 20 feet for the wire unless special circumstances prevailed. Modern current collectors are designed to have a reach of about the same distance [Ref}
Many alternative ways
have been suggested for getting power to the vehicles but none
of them is as straightforward, practical and proven as overhead
wire with rail return. Overhead wire does not have to show
up badly, and the supporting structure can be sympathetically
designed to suit the circumstances.
The Royal Fine Arts Commission has issued a circular
on aspects of tramway design
The possibility of running replica or genuine
heritage trams for the tourist trade should not be overlooked.
These will require a 550 volt D.C. supply but will only run on
selected routes. It should be possible to switch likely tourist
routes to this lower voltage during the appropriate season. For
safety reasons these will almost certainly have to be routes on
more-or-less level ground and the loss in performance of the standard
vehicles, because of the lower voltage on these sections, will
be insignificant.
Some modern trams will run satisfactorily on 600 volts, which
would also be within the safe working range of historic vehicles.
This could be adopted as a compromise between the two requirements
if dual-voltage operation proves unworkable for some reason; but
it would need closer-than-usual control to stay within limits
for both types of vehicle.
| Current collecting devices |
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