Pneumatic brake distributor valve assembly for a rail vehicle, comprising: - a brake cylinder pipe connector to connect to a brake cylinder pipe provided to be linked to a braking device configured to provide braking of an intensity according to the pressure in the brake cylinder pipe, braking having not to be carried out when the pressure in the brake cylinder pipe is atmospheric pressure, braking having to be carried out when the pressure in the brake cylinder pipe is greater than atmospheric pressure; - a train brake pipe connector to connect to a train brake pipe provided to be brought to a pressure of which the difference relative to a reference pressure represents the intensity of braking to perform, braking having not to be carried out when the pressure in the train brake pipe is similar to said reference pressure, braking having to be carried out when the pressure in the train brake pipe is less than said reference pressure; - a control reservoir connector to connect to a control reservoir provided to be brought to said reference pressure; - an auxiliary reservoir connector to connect to an auxiliary reservoir provided to store compressed air; - a main device in fluidic connection with said brake cylinder pipe connector, said train brake pipe connector, said control reservoir connector, said auxiliary reservoir connector and an exhaust to atmosphere, said main device being configured to selectively actuate a communication path between said brake cylinder pipe connector and either said exhaust or said auxiliary reservoir connector, according to the pressure at said train brake pipe connector and the pressure at said control reservoir connector, in order for the pressure at the brake cylinder pipe connector to be k times the difference between the pressure at the control reservoir connector and the pressure at the train brake pipe connector, k being a pre-set ratio of proportionality; - a cut-off valve in fluidic connection with said brake cylinder pipe connector, said train brake pipe connector and said control reservoir connector, said cut-off valve being configured to selectively actuate a communication path between said train brake pipe connector and said control reservoir connector, between a closed position and an open position, said path being in open position when the pressure at said brake cylinder pipe connector is atmospheric pressure and in closed position when the pressure at said brake cylinder pipe connector is greater than atmospheric pressure; and characterized in that said distributor valve assembly comprises a resetting device in fluidic connection with said brake cylinder pipe connector, said control reservoir connector and an air evacuation member, said resetting device being configured to selectively actuate a communication path between said air evacuation member and said control reservoir connector, between an open position and a closed position, said path being in open position when the pressure at said brake cylinder pipe connector is atmospheric pressure, and in closed position when the pressure at said brake cylinder pipe connector is greater than atmospheric pressure. - a brake cylinder pipe connector to connect to a brake cylinder pipe provided to be linked to a braking device configured to provide braking of an intensity according to the pressure in the brake cylinder pipe, braking having not to be carried out when the pressure in the brake cylinder pipe is atmospheric pressure, braking having to be carried out when the pressure in the brake cylinder pipe is greater than atmospheric pressure; - a train brake pipe connector to connect to a train brake pipe provided to be brought to a pressure of which the difference relative to a reference pressure represents the intensity of braking to perform, braking having not to be carried out when the pressure in the train brake pipe is similar to said reference pressure, braking having to be carried out when the pressure in the train brake pipe is less than said reference pressure; - a control reservoir connector to connect to a control reservoir provided to be brought to said reference pressure; - an auxiliary reservoir connector to connect to an auxiliary reservoir provided to store compressed air; - a main device in fluidic connection with said brake cylinder pipe connector, said train brake pipe connector, said control reservoir connector, said auxiliary reservoir connector and an exhaust to atmosphere, said main device being configured to selectively actuate a communication path between said brake cylinder pipe connector and either said exhaust or said auxiliary reservoir connector, according to the pressure at said train brake pipe connector and the pressure at said control reservoir connector, in order for the pressure at the brake cylinder pipe connector to be k times the difference between the pressure at the control reservoir connector and the pressure at the train brake pipe connector, k being a pre-set ratio of proportionality; - a cut-off valve in fluidic connection with said brake cylinder pipe connector, said train brake pipe connector and said control reservoir connector, said cut-off valve being configured to selectively actuate a communication path between said train brake pipe connector and said control reservoir connector, between a closed position and an open position, said path being in open position when the pressure at said brake cylinder pipe connector is atmospheric pressure and in closed position when the pressure at said brake cylinder pipe connector is greater than atmospheric pressure; and