Re: MORE TRAMWAY TRIVIA

["Ben Staples" <98711576@feline.hawkesbury.uws.EDU.AU>]

Ron BEST wrote in message ...

>I did mean to exclude crossings in Sydney and Melbourne between trams and
>underground railways, or between trams and underground roads, as in
>Melbourne with City Link. Sydney's light rail line poses some interesting
>dubious cases, however, and raises the hoary old question - when is a
bridge
>not a bridge, but a tunnel?? Anyone want to start a thread on this one?
>Rgds
>Ron BEST


My best guess about that tunnel question is that a tunnel is a structure
that does not directly support any live loading, i.e. any form of traffic or
wind. The tunnel would only support earth which is a dead (constant) load. A
bridge directly supports live loading.

Ben Staples