You can get rush drones from rare boxes on railjack bases. : r/Warframe
How do I use rush repair drones...? - Players helping Players - Warframe Forums
WARFRAME on Twitter: "We're making it easier to build your Railjack by reducing costs! If you've already started or finished Rising Tide, you'll receive a gift of Rush Repair Drones and refunded
Warframe Next Update Coming Next Week, See's Overhaul and Quality of Life Improvements - MP1st
Railjack – WARFRAME Support
I only got 7 rush repair drones from the Tier 3 railjack reward - Players helping Players - Warframe Forums
Steam-nyhedshub
Wegen unfairer Vorteile: Warframe entfernt kritisiertes Echtgeld-Item
Rush Repair Drone and 0.25% Drop chance - General - Warframe Forums
Warframe Update 27 Brings Empyrean, Here's the Huge Patch Notes List - MP1st
WARFRAME on Twitter: "Double your #Warframe's Mod capacity with Gift of the Lotus Alerts from last week's Devstream! Complete the Alerts before December 12 at 2 p.m. ET for a Rush Repair
Rank 10 Engineering doesn't actually repair anything. It DOES spawn a repair drone each time you try to use it, however... : r/Warframe