The gun could be gathered in only 3 days, but there was a need of 1000 men to build and transport it. The rails and the shoot support needed between 3 and 6 weeks of building for 1500 men. Gathering, preparing and using Dora wasn't an easy stuff.

Joachim Englemann says in his book «German Railroad Guns in action», [1976, Squadron/Signal publications ISBN 0-89747-048-6] that Dora needed :
·•An headquarters
·•A command post of the gun with a shoot control section
·•An intelligence reinforced half-company
·•a supervision half-company with 4 units equiped by Infra-red (very technology for the epoch)
·•one unit for the aiming and the corrections
·•the unit needed for the gun's building, using and un-building
All this stuff embodied 500 men.

Dora mustered all army corps :
·•Geny for construction
·•Anti-aerial artillery and a ground-ground missiles' detachment
·•Infantry with 2 Romanian guards companies
·•One unit of military police
·•One unit of dog handlers
·•One section of helicopters
·•An aerial covering from the Luftwaffe
·•20 civils engineers from Krupp

It represents a total of 3870 men !
Just for one shoot, Dora needed 350 men.