The BP-43 was designed in 1943 in an effort to incorporate the lessons that they had learned during the war to that point.  Their experience led to the use of two axle cars which were lighter and easier to produce than the heavy four axle cars used early in the war.  It also showed that multiple turrets in artillery cars were wasteful and vulnerable.  From 1943 onward the artillery cars were to use standard T-34/76 turrets and present as small a target as possible.  The number of machine guns was also reduced to two as this was deemed sufficient.

The typical BP-43 armored train consisted of an armored locomotive, a tender car, four PL-43 artillery cars, two PVO-4 anti-aircraft cars, and four security flatcars. The locomotive was typically of the OV or OK series that was covered with steel armor plates. It was also equipped with a DShK machine gun in an open position for air defense. A radio was located in the locomotive for communications with other friendly units. Internal communication was made possible by a system of speaking tubes, and light and tone signals. This system linked the engineers with the commanders of the artillery cars. Another interesting feature of the locomotive was that it had a steam heating system that was linked to all of its tender and artillery cars. The tender car (which was not always used) was armored in a similar manner as the locomotive, and mounted four Maxim machine guns in an anti-aircraft mount for air defense.

Artillery cars of the BP-43 were of the PL-43 type.  These were unique in that they were an armored flatcar with a square bunker in the center.  Atop this bunker was a T-34/76 tank turret with a single 76mm gun.  In each sidewall of the bunker a single DT machine gun in a ball mount was provided.  Vision slits, the optics of the main gun, and a hatch in the turret allowed the crew to observe the area around them.  Two small hatches in the bottom of the car allowed the crew to escape in the event of a severe hit.

The PVO-4 anti-aircraft cars were simple flat cars that had two 37mm M-1939 anti-aircraft guns placed on them.  These were placed at the front and rear of the car and surrounded by a box of thin steel panels as armor.  The panels were kept up and the guns faced the direction of travel when the train was in route, but the panels were folded down when the guns engaged aircraft.

Security cars completed the train and were simple flatcars attached to either end.  They carried tools, spare ties, connectors, and track sections for repairing damaged sections of track.  Often they would be manned by a small infantry unit who used sandbags and railroad ties for cover.  These troops would act as observers and often dismount if the train was attacked.

Twenty one BP-43 armored trains were delivered to the Red Army by the end of 1943.  Many of these would see heavy combat across the Eastern Front.  Some led breakouts near Kiev, while others pushed into Eastern Europe as the Red Army advanced.  

An unknown number of BP-43 trains were made for the NKVD during the war.  At least eight of these armored trains were used by Joseph Stalin when he traveled to the Potsdam Conference in July 1945.  It can be supposed that the NKVD continued to use these trains after the war, but of this little information has been released.  The same can be said for the BP-43 armored trains used by the Red Army as Soviet sources say little about their post-war fate.  Some few ended up in war museums (one is preserved at the Moscow Army Museum) and the remainder were most likely scrapped.

The BR-43 trains of the Red army were assigned to armored train battalions made up of two trains.  In this role they were used as assault elements, escorts for troop trains, and as mobile strongpoints for defending troops.  The BP-43 trains of the NKVD were used to patrol border regions and as part of Stalin's escort when he traveled by rail.

They shared the advantages of other armored trains in that they could bring large amounts of artillery to bear on a target, carry large amounts of ammunition, and move into an area quickly - often by surprise.  It could also cover up to 500 kilometers of ground each day.  The train's heavy  armor rendered it immune to small arms and shrapnel, and it also carried its own anti-aircraft armament.  Its machine guns also enabled it to provide friendly infantry with cover fire.

As a class the BP-43 train had the best artillery cars of any Soviet armored train - the PL-43 car.  These two-axle cars were heavily armored and had a very small target silhouette.

Its limitations were those common to any armored train, primarily the fact that its maneuverability was limited by its tracks.  In many cases armored trains were trapped when the tracks ahead of them and behind were destroyed.  They were also exceptionally vulnerable to air attacks.  The trains were also very dependant on their bases for support as water and coal had to be taken on daily.  As the war progressed they also proved to be less effective than tanks when it came to engaging other armor units.