EMPTY/LOAD DEVICE TRAINING

1
EMPTY/LOAD DEVICE TRAINING

• MODEL SERIES
• 6200, 6600, ENX

2
Part I. How it Started
One of the issues that freight car designers face
today is to achieve the maximum braking
effectiveness on a car whether it is empty or
loaded. Todays cars are being constructed much
lighter than in years past, yet they carry
heavier loads. If these cars were to utilize the
same braking forces from years ago, it would
result in brake related wheel defects like,
shelling, flat spots and so on. The greater the
weight of a moving object, the greater the force
required to slow it down and bring it to a
complete stop. An empty freight car requires less
braking force to slow it down or stop it compared
to a loaded car. To solve this issue, the
Empty/Load device was created to limit braking
forces while the car is empty and maximize the
braking force in loaded condition.
3
How it helps

• Single capacity air brake equipment cannot
  recognize whether the car is empty or loaded. As
  a result, the brakes apply in proportion to the
  brake pipe pressure reduction, regardless of the
  weight of the car. With a heavy service brake
  application, a light car may be over-braked when
  it is in empty, which may result in the
  following
• Flat spots on wheels due to sliding
• Shelling of the wheels
• Premature removal of brake shoes
• Increased damage to rail
• To order to prevent these over-braking issues,
  the empty/load device was developed.

4
How it works Part A Principles of Empty/Load
Braking

• Most empty/load brake equipment is not designed
  for a variable car load, which means that it does
  not proportion the braking force to the load of
  the car. The device only detects if the car is
  empty or loaded, not partially loaded. Typically,
  if the car is loaded to 20 or more of its
  capacity, the car is considered to be loaded and
  is braked as if it were loaded.
• We must first understand that the retarding force
  on the car is directly dependent upon the
  pressure developed in the brake cylinder. So, we
  must reduce the brake cylinder pressure to reduce
  the braking force. Therefore, it is necessary to
  determine if the car is empty or loaded and then
  adjust the brake cylinder pressure accordingly.

5
How the load is detected

• At this point there are 2 methods of detecting
  the load of a car. They are the Arm-type
  detecting devices and the Slope sheet canister
  detecting device.

• Principles of the Arm-Type Sensing Devices.
• When a car is empty, the truck springs have
  only the weight of the car on them and are in a
  relaxed state. As the car is loaded, the springs
  will compress. So, by measuring the amount of
  spring deflection we can determine whether the
  car is empty or loaded.
• A common method of measuring the spring
  deflection is by using a moveable sensor arm or
  piston that is part of a valve mounted on the
  car. As air is applied, the sensor arm or piston
  will rotate or extend to touch the side frame or
  a bracket located on the side frame. The
  empty/load device detects the change in distance
  between the initial setup position and the side
  frame and deflects the air pressure accordingly.

6
MODEL 6600 EMPTY/LOAD VALVES

• 6600-1
• 6600-2 6600-1U

7
Versions of the Arm-Type Empty/Load

6600 Series ELRP SC-1
ENX EL- ELX-U
8
The Arm Type System

• This system is typically comprised of 3 parts
  depending on the application. These parts are

Reservoir
Sensing Valve (S1)
Proportional Valve (P1)
Located in specific places in the braking system,
all have a unique job in the braking process. The
Sensing Valve is located over the bolster side
frame and senses whether the car is empty or
loaded. Air is either blocked and returned to the
brake cylinder or passed through to the
proportional valve and reservoir. cont
9
Cont

• The Proportional Valve located between the
  Control Valve and the Brake Cylinder, deflects
  the air away from the brake cylinder into the
  reservoir, therefore reducing the brake cylinder
  pressure and braking force.
• The Reservoir is an empty canister that is a
  holding tank for the deflected air.

10
6600 SERIES VARIATIONS

• 6600-1 This valve is a standard 60 valve, which
  will reduce the cars brake cylinder pressure to
  approximately 60 of the loaded car pressure when
  the car is in empty condition.
• Mounted to the car structure, the valves 3
  piece construction is used on the standard
  freight cars or end trucks of 5-unit articulated
  cars.
• 6600-2 This valve is a standard 60 valve like
  the 6600-1 with 3 piece construction for use in
  areas where the 6600-1 cannot fit.
• 6600-1U This valve is a standard 60 like the
  6600-1, but it is condensed into one piece or
  unitized piece. It is used on the intermediate
  trucks of the 125 ton articulated 5-unit double
  stack cars.
• NOTE These valves have all have a 50 version
  where the valve will reduce the brake cylinder
  pressure by 50 for empty car condition.

11

1. PROPORTIONAL VALVE

The Proportional Valve is mounted in the brake
pipe between the Air Brake Valve and the Brake
Cylinder, so the air pressure must go through the
Proportional Valve before it gets to the Brake
Cylinder. The Proportional Valves primary
function is to provide a balance of brake
cylinder pressure and equalizing reservoir for an
empty brake application. When a empty car load is
detected, a percentage of the air pressure is
deflected away from the brake cylinder to the
reservoir. Depending on the weight of the car, a
50 valve will send 50 of air pressure to the
brake cylinder and a 60 will send 60 of the air
pressure to the brake cylinder. The 50 is NOT
interchangeable with the 60 proportional valve.
Pipe Bracket
Proportional Valve
Indicator
12
3. Equalizing Reservoir

• The Reservoir accepts the deflected air pressure
  from the proportional valve during an empty
  application.
• It is located between the Sensor Valve and the
  Proportional Valve.
• The primary function is to provide air pressure
  balance with the brake cylinder.

13
Understanding the Air Flow

• Downstream Valves
• 6600 Series

14
Downstream (6600) Charged
Reservoir
Aux
Emergency
Reservoir
SensorValve
ControlValve
RelativePressure
High
ProportioningValve
Brake Cylinder
Brake Pipe
Low
15
Downstream (6600) Minimum Application
Reservoir
Aux
Emergency
Reservoir
SensorValve
ControlValve
RelativePressure
High
ProportioningValve
Brake Cylinder
Brake Pipe
Low
16
LOADED CAR
17
Downstream (6600) Full Service Car Loaded
Reservoir
Emergency
Aux
Reservoir
SensorValve
ControlValve
RelativePressure
High
ProportioningValve
Brake Cylinder
Brake Pipe
Low
18
Downstream (6600) Valve Detail Car Loaded
Sensor motion limited by car side frame,
detecting loaded car.
Air passes directly through the sensor to the
cylinder.
19
Downstream (6600) Emergency Car Loaded
Reservoir
Aux
Emergency
Reservoir
SensorValve
ControlValve
RelativePressure
High
ProportioningValve
Brake Cylinder
Brake Pipe
Low
20
EMPTY CAR
21
Downstream (6600) Full Service Car Empty
Reservoir
Aux
Emergency
In Empty condition, the arm fully extends,
allowing proportional air to be diverted to the
reservoir.
Reservoir
SensorValve
ControlValve
RelativePressure
High
ProportioningValve
Brake Cylinder
Brake Pipe
Low
22
Downstream (6600) Valve Detail Car Empty
Pressure equalizes.
RelativePressure
High
Low
Sensor motion not limited
To Reservoir
Indicatorextends
Proportional spool divides pressure
23
Downstream (6600) Emergency Car Empty
Reservoir
Aux
Emergency
In Empty condition, the arm fully extends,
allowing proportional air to be diverted to the
reservoir. This occurs during Emergency
application as well, but the pressures are a
little higher.
Reservoir
SensorValve
ControlValve
RelativePressure
High
ProportioningValve
Brake Cylinder
Brake Pipe
Low
24
Downstream (6600) Valve Detail Exhaust
RelativePressure
High
Exhaust valve opens
Low
To Reservoir
Check valve opens
Exhaust
25
MODEL ENX EMPTY/LOAD VALVES
26
Reservoir
Aux
Emergency
TMB Cylinder
3 Pipe
RelativePressure
Reservoir
High
Valve
Upstream (ENX) Charged
Brake Pipe
Low
27
To Cylinder
From Control Valve
There is not enough air in the system to force
the arm to drop.
Side Frame
RelativePressure
High
Upstream (ENX) Minimum Application
Low
28
LOADED CAR
29
Reservoir
Aux
Emergency
TMB Cylinder
Reservoir
Control Valve
RelativePressure
Valve
Side Frame
High
Brake Pipe
Upstream (ENX) Full Service - Loaded
Low
30
To Cylinder
From Control Valve
Port to Reservoir closed
The arm is limited by the side frame..
Side Frame
RelativePressure
High
Upstream (ENX) Full Service - Loaded
Low
31
Reservoir
Aux
Emergency
TMB Cylinder
Reservoir
RelativePressure
Valve
High
Side Frame
Brake Pipe
Upstream (ENX) Emergency - Loaded
Low
32
To Cylinder
From Control Valve
Side Frame
RelativePressure
High
Upstream (ENX) Emergency - Loaded
Low
33
EMPTY CAR
34
Reservoir
Aux
Emergency
TMB Cylinder
Reservoir
Control Valve
Valve
RelativePressure
High
Side Frame
Brake Pipe
Upstream (ENX) Full Service - Empty
Low
35
From Control Valve
To Cylinder
To Reservoir
Port to Reservoir opens
RelativePressure
Indicator extends when arm drops and
pressure reaches 15psi.
High
Upstream (ENX) Full Service - Empty
Side Frame
Low
36
Reservoir
Aux
Emergency
TMB Cylinder
Reservoir
RelativePressure
Valve
High
Arm fully extended
Side Frame
Brake Pipe
Upstream (ENX) Emergency - Empty
Low
37
From Control Valve
To Cylinder
To Reservoir
Arm drops when air is applied. Load is not
detected, So port to reservoir opens and air is
displaced.
RelativePressure
High
Arm not limited by Side Frame in empty position.
Upstream (ENX) Emergency - Empty
Low
Side Frame
38

• MODEL 6200 EMPTY/LOAD VALVES
• 6200-5B
• 6200-50/50
• 6200-5/30
• 6200X-40B

39
3. Versions of the Slope Sheet Mounted Empty/Load

6200 Series ELS
40
6200 SERIES VARIATIONS

• There are basically three (3) members of the 6200
  Series valve family. Each is designed to conform
  to specific car construction or customer
  requirements. Each delivers a percentage of the
  loaded car pressure when the car is in empty
  condition, thus reducing the effective braking
  force. They are as follows
• 6200X-40BF This is a standard 40 valve which
  delivers 40 of the loaded pressure to the Brake
  Cylinder during empty car condition. This lower
  braking force is necessary due to the trend
  toward building lighter aluminum cars while
  designing it for the current 286,000 lb Gross
  Rail Load.
• 6200-5 This is a standard 60 valve which
  delivers 60 of the loaded pressure to the Brake
  Cylinder during empty car condition. This valve
  is designed for cars with heavier light weight
  conditions.

41
6200 SERIES VARIATIONS

• C) 6200-50/50 This is a 50 valve with a
  standard change over point of 17psi. It is
  designed for intermediate light weight cars.
• Note Although the 6200-5, 6200X-40 and the
  6200-50/50 are all applied and tested the same,
  the valve operating portions (replacement
  portions) are not interchangeable. If a valve
  operating portion needs to be replaced, it can be
  identified by its model number, which is machined
  into the front surface of the valve body.

42

• GENERAL
• The following tests and inspections are to be
  performed in conjunction with the latest revision
  of the AAR Code of Air Brake System Tests for
  Freight Equipment, Standard S-486, latest
  revision, special tests section, auxiliary
  devices sub-section.
• INSPECTION
• Before proceeding with testing of empty load
  equipment, the following inspection should be
  performed
• Inspect for any general damage to empty load
  valve, including dents or punctures. (Replace if
  obvious defect exists.)
• Check for secure attachment of empty load valve
  to slope or floor sheet of car. (Make any
  necessary repairs.)
• Inspect pipe or hose connections for secure
  attachment. Make sure hoses or pipes are free
  from cuts, cracks, or other damage or defects.
  (Replace if necessary.)
• Check hose or pipe connections for proper
  installation. Empty load valve will not function
  properly if piped incorrectly. (Make adjustments
  if necessary.) (See Figure 1.)

43

• TESTING
• LOADED CAR MODE
• Locate and remove uppermost machine screw and
  lock washer. (See Figure 2.)
• Insert test handle (see Figure 3) into vacant
  hole. This will place empty load valve into
  loaded mode.

44

• Make 20 psi reduction using single car test
  device. With brakes applied, check to see that
  indicator stem is not extended, indicating that
  empty load valve is in loaded mode. (See Figure
  4.)
• Release brakes by placing single car test device
  handle into Position No. 1. Brake cylinder
  piston should retract and air should exhaust from
  retaining valve only.

45
Empty Car Testing Procedure

• Following test can only be conducted on an empty
  car.
• After completion of loaded car test, remove test
  handle and replace machine screw and lock washer.
• Do not over-tighten, as no seal is required at
  this point.
• Make 20 psi reduction using single car test
  device. With brakes applied, check to see that
  indicator stem has extended, indicating that
  empty load valve is in empty mode. (See Figure
  5).

46

• Release brakes by placing single car test device
  handle into Position No. 1. Brake cylinder
  piston should retract and air should be heard
  exhausting through retaining valve and possibly
  through empty load valve vent protector as well.
  Indicator stem should no longer extend.

Note If empty / load valve does not pass above
tests, or is damaged or defective, it must be
replaced with reconditioned or new valve body.
47
Downstream (6200) Charged
RelativePressure
High
Aux
Emergency
Reservoir
Low
ControlValve
Brake Cylinder
Brake Pipe
48
Downstream (6200) Minimum Application
RelativePressure
High
Aux
Emergency
Reservoir
Low
ControlValve
Brake Cylinder
Brake Pipe
49
Downstream (6200) Full Service Car Loaded
RelativePressure
High
Aux
Emergency
Reservoir
Low
ControlValve
Brake Cylinder
Brake Pipe
50
Downstream (6200) Emergency Car Loaded
RelativePressure
High
Aux
Emergency
Reservoir
Low
ControlValve
Brake Cylinder
Brake Pipe
51
Downstream (6200) Full Service Car Empty
RelativePressure
High
Aux
Emergency
Reservoir
Low
ControlValve
Brake Cylinder
Brake Pipe
52
Downstream (6200) Emergency Car Empty
RelativePressure
High
Aux
Emergency
Reservoir
Low
ControlValve
Brake Cylinder
Brake Pipe
53
Downstream (6200) Valve Detail Car Loaded
Product pushes against diaphragm
Diaphragm pushes rod, forcing spool to cut off
port to reservoir.
Indicator
With port sealed, air flows through the valve
into the brake cylinder
54
Downstream (6200) Valve Detail Car Empty
No product
Car Body
Indicator Pops
With reservoir port open, proportional air fills
the reservoir.
55
Figure 5
Conventional Brake System
Truck Mounted Brake System