Re: Lift out bridge

["Ira Schneider" <ira_schneider@iname.com>]

As Bill said, we have been discussing the possibility of building some sort
of entry way to the layout for years.  I would hate to see us rush into implementing
something just because several people are "gung-ho" on doing something now.

If we are going to build something, we need to completely understand the
implications, both structural and practical.

For example, the way we assemble our layout there are high shear forces
on the modules.  With a rectangular layout, there is no problem.  However,
with an L-shaped layout, there is a gap of 2-1/4" (in both directions) in the
layout.  We are able to force this gap closed by man-handling the modules.
At the last show, the gap appeared to be larger, probably due to the way
we assembled the layout.  With our current straight modules, there is
no weak point in a module.  With a bridge, we need to find some way to
keep the module intact, even though there can be no structural member
crossing the gap at track level.  The only structural member would be
at floor level, which may not be able to hold the tracks together properly.

We also need to decide how and when this bridge could be operated.
I have seen suggestions that the bridge would only be opened during
setup and teardown.  If this is so, is it really worth the effort?  We
normally leave a gap in the layout until we finish assembling the modules,
leaving a space for people to move in and out of the layout.  If we will
open the bridge while running the layout, how will this affect operations?
We have four operators running trains simultaneously.  They all have
to stop their trains when the bridge is open.  Is this something we
really want to do during a show?  If so, how often will this be allowed?

Another thing to consider is how this module will be stored in the trailer.
As Bill pointed out, the trailer is currently pretty well packed with
equipment.

I don't object to the concept of designing a bridge module, as long as
all factors are considered.  I just don't want to see us rush into implementing
something without completely understanding all implications.  And, yes,
I am comparing this to the 45 degree corners.  We discussed them for
several years, then suddenly rushed into implementing them without
fully understanding the implications, including the fact that we need a
much larger space for the layout when using the new corner modules and
that they take up more space in our already packed trailer.  Also, we
currently have only two pairs of the 45 degree modules.  Even though
they look nice, they don't provide any improvement in operating large
trains since we still have to use at least two of the older corners, which
have smaller radii tracks.  Also, using a pair of the new corners for the
inside corner of an L-shaped layout didn't completely solve the problem
of track 1 being the inside (i.e. smallest radius) track since we still
have collisions between trains on tracks 1 and 2.  In my opinion, the
design for these modules was rushed into the implementation phase
without fully considering how they would perform in our layout.
I don't want to see the same thing happen with a bridge module.


Ira