Found for sale on eBay, two 35mm slide scans. (One is darker due to underexposure during scanning, most likely.) Original photographer credit unknown.
Left is old Engine 4, a 1997 E-One Cyclone II, 1250/500. Right is old Engine 6, a 1990 Duplex D-500/E-One, 1250/500. Readers can check/correct my data.
Here’s a Legeros Blog Fire Archives posting with a first-stab at a DFD fleet listing, from 2014.
Click to slightly enlarge: