dressed up the mountainsides. The rocky
gorge and the rushing river at its bottom
were matched by using photographs of the
actual scene as guides.
Water Pipes Add Swirls
There's more to creating a realistic river
in flood stage than you might think, even in
miniature. One of the problems is the sheer
volume of water required. This was solved
by storing all the water in a small reservoir
and in a number of huge dump tanks, all
upstream out of camera range. When the
water was released into the river a satisfactory flood came pouring downstream.
But the torrent didn't have the swirling
white crests and the swift treacherous currents of an actual river in flood, so these
were added artificially. Water pipes were
laid in the river bed with spray heads attached to provide swirls of current.
Pipe Collapses Trestle
Lee Zavitz explains that building the
miniature trestle was easy, but engineering
it so that it would collapse at the right time
and in the right manner took a lot of
thought. The trestle was built of wood, each
small stick representing an actual timber
in the real structure. Construction details
had to be perfect. A flaw such as a hammer
,mark around a nail would be magnified to
the size of a basketball on the screen, giving
away the whole scene.
"After the trestle was built we placed
a four-inch pipe across its bottom, extending from one-side of the river to the other,"
Zavitz says. "The pipe was hidden by the
water. Then we ran concealed cables from
various parts of the trestle down to the
pipe and attached them at different points.
Thus, when the pipe was rotated by a motor
the cables wound around it. The cables
tightened one at a time and successively
brought down different portions of the
trestle. The whole collapse had to occur in
just the same way that an actual trestle
would weaken and fall."
The scaled-down train used in the scene
was a modern miniature that was rebuilt
to match the actual train used in Colorado.
Such details as the engine cab, stack, headlight and whistle were all reproduced exactly. Batteries were
used for interior lighting. The engine had its own boiler and
produced its own steam. Black smoke for
the stack came from a smoke cartridge.
"It would have been simple to send the
train across the trestle under its own
power," Zavitz remarks, "and we might
have done this if the story called for the
train to run off the trestle and crash in the
river. But the running of the train