Ok, after much searching I cannot find what I'm looking for, so I am improvising - attached are 2 pictures - 1 of the original "Rapid Response 3" and 1 of the truck in it's older "Bush Buggy" configuration (I believe they are from Jay_911 but I'm not completely sure, so credit to the photographer). Being that the truck is labelled "TR 1700" I assume the rapid response program ran from the year 2000 on until maybe 2001-02? that's a guess, but I don't imagine it lasted long..
This is a link to Hub fire truck's website
Salmo — HUB Fire Engines - RR3 was similarly designed to the truck displayed here -notice the pump set-up! I can't find the other pictures I am looking for with regards to the pump set-up and model but it is similar.
Long story short, from what I recall (and if you have more info PLEASE chime in) CFD ran RR3 out of Station 36 (Used to be called Station 3 in Hidden Valley) as then a front line pumper - with 4 ff's. They responded once or twice on a house fire first due and simply didn't have enough pump capacity to knock the fire down let alone put a second line into operation (I don't remember if the pump they had could even run a second hand line) Regardless, a second Engine arrived (along with the rest of the first alarm) more lines were stretched and the fire was knocked down.
The big picture thinking of CFD at the time was maybe they could replace big front-line Engines with these smaller snuffer/mini-pumper style trucks, but they could not. They tried the same things with the Rescues - using a smaller mini-rescue from SVI, same thing. Just couldn't carry all the equipment and get the job done.
Anyways, from there RR3 was turned into a Bush Buggy (second picture) things were changed on the truck and it served all over the city from 8 Station to 13 Station and so on.. eventually the pump and tank were removed or at least the pump was and was replaced for a Rosenbauer UHPS Pump (what's on the current 2010/15 BB's) (That pump and tank are removable keep in mind) from there it served as an Medical Response Unit to today were it is the "Special Events Truck" - likely until its retired.
In theory (at least how I see it) it's essentially a spare Bush Buggy but the pump/tank can be removed (like the 2010/15's) and it can serve as a mini-rescue or whatever else its needed for.
I hope this answers your question JABoomer 😅