[alma-config]Re: transporter

[mel wright 456]

Hi all,

It would be interesting to know what is the rational behind this design,
which looks
to the unitiated -- how to put it ?  does ALMA have a good insurance
policy ?

Driving over pads.

> All existing reconfigurable arrays
> I am aware of have transporters that drive
> over, or at least straddle, the pads.  This
> has not caused any problems that I am
> aware of.

1. Of course, most of the existing arrays have rails which
distribute the load nicely.

2. there  are some pad settling problems from time to time
at hatcreek after an antenna is moved.
It is not clear if these are related to driving
over pads.

There are several problems not addressed by the current
ALMA design.

John Lugten detailed several. Here are a  some more

1.  compact configuration. - steering around other antennas
                                           - safely of other antennas
2.  tire failure backup - transporter stability.

A dual  wheeled transporter should be considered;  using tires for
long distance and rails for  guidence,  safelty, and avoiding driving
over
pads at the stations..What I have in mind is something like  a Paris
Metro
,  with steel wheels and tires.  The steel wheel also acts as a backup,
allowing the transorted to gracefully sink into the dirt, rather than
dropping  rapidly when a tire fails.

At least I'd liketo know why should be rejected.

cheers,

Melvyn