Operation & Maintenance Instruction
Page 2 of 24
August, 2003
4225-50, S.6
1.0
DESCRIPTION
The AB Single Capacity Freight Car Air Brake Equipment
with the ABDX Type Control Valve is functionally compatible
with equipments using the AB, ABD or the ABDW Control
Valve. Correct style of ABDX Control Valve must be applied
to specific length cars.
The ABDX Type Control Valve improves service braking by
providing both a shorter response time and a shorter brake
cylinder pressure build up time. The initial quick service
function has been improved through a new service piston,
diaphragm and diaphragm clamping arrangement.
Other benefits of the ABDX Type Control Valve include
improved undesired emergency (UDE) protection, improved
protection against leakage, and the elimination of the need
for auxiliary continuous quick service valves.
1.1
PARTS OF THE EQUIPMENT
The following is a description of the Control Valve which is
part of the AB Freight Car Air Brake Equipment with the ABDX
Type Control Valve:
1.1.1
ABDX TYPE CONTROL VALVE
The ABDX Type Control Valve controls the flow of air to and
from the brake cylinder and to charge the reservoirs. It consists
of a Pipe Bracket, a Service Portion and an Emergency
Portion.
1.1.2
PIPE BRACKET
The ABDX Control Valve uses the AAR AB type pipe bracket.
This is a two-face pipe bracket to which are mounted the
service and emergency portions. Figures 2 and 3 show the
port identification on each face. The pipe bracket is semi-
permanently bolted to the car. Pipe connections may be made
by means of adjustable welded fittings secured to machined
flange pads on the pipe bracket. No pipe connections need
to be disturbed when removing or replacing the service or
emergency portion. The pipe bracket contains the quick action
chamber and a removable strainer which provides long life by
minimizing the passage of dirt particles to the valve and brake
cylinder.
Pipe Connections
- Figure 4 shows the pipe bracket face
to which the pipe connections are made. Each port
connection is identified by number and name.
Figure 1 - Diagrammatic View
