[emchammer]

The shafts are so enormous and heavy that they must be driven by an auxiliary motor when not in use in order to prevent them from permanently sagging.

[kencausey]

I assume this sag is something that would only become relevant over a fairly long period of time? Otherwise how were the devices constructed originally, I doubt they were spinning instantly.

[ethbr1]

They can presumably be fully braced when not in use, but not in the application?