A parking brake valve assembly for a pneumatic braking system of a vehicle includes a first parking brake valve unit and a second parking brake valve unit. The first parking brake valve unit is actuated by a first parking brake signal and is switchable from a first to a second switching position, and the second parking brake valve unit is actuated by a second parking brake signal and is switchable from a first to a second switching position. The first and second parking brake signal are mutually independent. The first and second parking brake valve unit are pneumatically connected in series between a parking brake supply connection and a parking brake working connection such that the parking brake working connection can be both ventilated and vented independently of the switching position of one of the parking brake valve assemblies by switching the other parking brake valve assembly.

Disclosed is a rolling unit (8) for a test rig (1) for testing an automatic underground train, including: two rolling belts (27), each one provided for a wheel (6) of the train to roll thereon, the wheels driving the movement of the belts; and a rotary inertial body (28); each belt including: a pinion (31) that is rotatably connected to the inertial body; two rollers (33); and a grooved rolling surface (32) mounted on the rollers, meshed with the pinion, and forming a rolling area (34) for a respective wheel between the rollers.

Disclosed is a rig (1) for testing an automatic underground train (2), including at least two rolling units (8) at a distance from each other, each one provided for rolling at least one wheel (6) of the train (2) thereon, each unit (8) including: a rotary inertial body (28); a motor (26) engaged with the inertial body; and a sensor (51) for the rotational speed of the inertial body; the rig also including a unit (11, 15) for controlling each of the motors (26) so as to permanently eliminate any difference in speed between the rolling units.

Disclosed is a rig (1) for testing an automatic underground train (2), including at least two rolling units (8) at a distance from each other, each one provided for rolling at least one wheel (6) of the train (2) thereon, each unit (8) including: a rotary inertial body (28); a motor (26) engaged with the inertial body; and a sensor (51) for the rotational speed of the inertial body; the rig also including a unit (11, 15) for controlling each of the motors (26) so as to permanently eliminate any difference in speed between the rolling units.

A compressed air supply device for operating a pneumatic installation comprises an air supply unit configured to supply air, an air compression unit configured to compress air, a bleeding line comprising a controllable solenoid valve arrangement, the solenoid valve arrangement having a magnetic part and a pneumatic part, and a bleeding port configured to bleed air. The device also comprises a compressed air supply line having an air drier and a compressed air port, the compressed air supply line being configured to supply the pneumatic installation with compressed air, wherein the pneumatic part is open when the magnetic part is not activated.

A trailer having an aerodynamic skirt that includes a valve access panel is disclosed. The trailer includes a tank for transporting cargo and a valve at the base of the tank for accessing unloading the cargo from the trailer. The aerodynamic skirt extends along a first side of the trailer body that includes the valve and a valve access panel that is configured to cover the valve when closed and to allow access to the valve when open. The apparatus also includes a trailer brake interlock that is communicatively coupled to the valve access panel and a trailer brake to restrict motion of the trailer when the valve access panel is open and to permit motion of the trailer when the valve access panel is closed.

A trailer having an aerodynamic skirt that includes a valve access panel is disclosed. The trailer includes a tank for transporting cargo and a valve at the base of the tank for accessing unloading the cargo from the trailer. The aerodynamic skirt extends along a first side of the trailer body that includes the valve and a valve access panel that is configured to cover the valve when closed and to allow access to the valve when open. The apparatus also includes a trailer brake interlock that is communicatively coupled to the valve access panel and a trailer brake to restrict motion of the trailer when the valve access panel is open and to permit motion of the trailer when the valve access panel is closed.

A trailer having an aerodynamic skirt that includes a valve access panel is disclosed. The trailer includes a tank for transporting cargo and a valve at the base of the tank for accessing unloading the cargo from the trailer. The aerodynamic skirt extends along a first side of the trailer body that includes the valve and a valve access panel that is configured to cover the valve when closed and to allow access to the valve when open. The apparatus also includes a trailer brake interlock that is communicatively coupled to the valve access panel and a trailer brake to restrict motion of the trailer when the valve access panel is open and to permit motion of the trailer when the valve access panel is closed.

A trailer having an aerodynamic skirt that includes a valve access panel is disclosed. The trailer includes a tank for transporting cargo and a valve at the base of the tank for accessing unloading the cargo from the trailer. The aerodynamic skirt extends along a first side of the trailer body that includes the valve and a valve access panel that is configured to cover the valve when closed and to allow access to the valve when open. The apparatus also includes a trailer brake interlock that is communicatively coupled to the valve access panel and a trailer brake to restrict motion of the trailer when the valve access panel is open and to permit motion of the trailer when the valve access panel is closed.

A driver side brake controller can include a telescoping shaft including a brake lever connector disposed thereon and adapted to be secured to a brake lever of a motor vehicle. A tubular main body can be provided that is adapted to adjustably accept the second telescoping end of the telescoping shaft therein and secure the telescoping shaft with locking hardware at a fixed position within the tubular main body to enable the main body to extend from the driver-side front floorboard area up into the driver side compartment near a steering wheel and within reach of a driver's hands. The tubular main body can terminate at a handle area that can be padded. The tubular main body can be rotated 360 degrees to allow for either hand (left, right) operation. Rotation can be facilitated by a swivel joint connecting the telescoping shaft and the brake lever connector.