BTR is the acronym for "Bronetransporter", translated from Russian as 'armored transporter'. The BTR-40A fire support/anti-aircraft vehicle was developed concurrently with the BTR-40 Scout Car although came into service a little later.  Although many sources state that this solely a SPAAG system, the intended Soviet role was also to use for ground fire support.

There was only one variant of this vehicle, the BTR-40A ZhD rail fire support vehicle.  This variant was only produced in very small numbers.