Automatic Parking Brake
 

 
The CLC-APBL Automatic Parking Brake for locomotives is designed as a back-up brake to the standard locomotive handbrake. It does not take the place of the standard handbrake nor does it relieve the owner of any responsibility for setting the standard handbrake.  Its more like insurance, you hope you don't need it but its nice to have it anyway. 
The CLC-APBL works totally independently of the handbrake.  It is mounted on and operates the brake rigging on the locomotive truck that is not equipped with a standard handbrake.  Normally only one truck is equipped with a handbrake on switcher locomotives.  The CLC-APBL design uses a heavy coil spring to apply the parking brake and air pressure operating through a pneumatic cylinder to release the brake.  If the locomotive's air pressure fails below set point or if the locomotive engine stops for any reason the CLC-APBL unit applies the parking brake.  In order to release the brake the engine must be running and the air pressure on the locomotive's dry air receiver must be above set point pressure.
A continuous duty electrical solenoid is held open to supply air to keep the brake off during normal operation.  If the power fails to the solenoid for any reason the automatic parking brake will apply immediately.   This is a nice feature for industrial plants which often have significant grades.
Under normal circumstances if a locomotive is parked on a grade and if the operator fails to set the locomotive handbrake then over several hours the locomotive will loose air pressure and this will release the regular locomotive brakes.  A locomotive requires air pressure to apply its brakes.  That is why setting the handbrake is so important.  If it is parked on a grade the air pressure is subject to bleed down over time and the locomotive can simply roll off down the grade.  With the CLC-APBL unit approximately the same brake pressure will be automatically applied by the coil spring to its truck as would be applied by a standard handbrake to the other truck when the handbrake is fully tight.  If both the handbrake and the CLC-APBL are set then both trucks are locked down and the brake system can withstand significant gravity forces.
Remote start-stop is handy when operating radio remote control.  Some applications require stopping the engine during loading of flammable products.  CLC requires the automatic parking brake option be installed on any locomotive prior to installing remote start-stop.  Even on flat track the string is subject to being bumped.  You always want to insure that anytime the locomotive is not under the control of its standard brakes that it is under the control of the handbrake and possibly the automatic parking brake.  Unlike other automatic parking brakes for locomotives the CLC-APBL design does not require any electrical or pneumatic power whatsoever to apply the parking brake.  The coil spring does all of the work.  It only requires power to release the parking brake.

 

 
Warning: This CLC-APBL automatic parking brake is a new product and is not FRA, MSHA, or OSHA approved to replace the locomotive handbrake or to relieve the owner from the responsibility of applying the handbrake. 
 

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