Priority Alarm System

Identifies the type and location of Passenger train Emergencies. Description The Bach-Simpson Priority Alarm System (PAS) provides a means of monitoring abnormal conditions in the cars of a passenger train that could affect human and/or equipment safety. The PAS signals train crew members when situations arise that require a high-priority response such as a fire in a car, an open door while the train is moving, dragging brake equipment or, most importantly, a call for help by a passenger in need of emergency assistance. The Priority Alarm System identifies the nature and location of an alarm in the train allowing the engineer to direct the conductor or another crew member to investigate the trouble and take appropriate action. How The System Works Sensing devices are connected to a Remote Alarm Unit (RAU) in each passenger car. The RAU processes an alarm signal, activates warning devices within the car and relays the signal, via the trainline, to a Master Control Unit (MCU) located in the locomotive or cab control car. Audible and visual alarms are activated at the engineer's station. A message, identifying the kind of problem which has been detected by the System and its location are displayed on a Display Head indicator in the cab.

In addition to sensing devices installed in the cars, the Remote Alarm Unit will accept signals from dragging brake and car-door-open-while-moving alarm circuits. When alarm signals originate in a car as a result of a Passenger Assist Strip being pressed, or in response to Heat and/or Smoke Detectors being activated, the RAU will also cause a red light on the outside of the car to flash on and off to signal the location of the emergency in the train.

To respond to an alarm and message, the engineer must call a crew member by radio or intercom to investigate the situation. After responding, the crew member can reset the Remote Alarm Unit in the car to deactivate the alarms.

The alarms and reset actions can be recorded by a Bach-Simpson Event Recorder. In addition to the recorder, the locomotive or cab car frequently will also have an alertness control device such as the Bach-Simpson Train Monitoring System (TMS).

The general configuration of the Bach-Simpson Priority Alarm System is as shown in Figure 1:

Priority Alarm System Operation
The PAS will normally operate in either of two basic modes; Alarm System Active or Alarm System Shut Down.

In the Alarm System Active mode, one MCU in the train is active and has control of the alarm system. This will be at the engineer's location whether it is in the locomotive or in a cab control car. A non-active MCU at the opposite end of the train will display alarm messages, but will not activate audible signals unless the engineer does not respond to the alarm at the controlling end within a prescribed length of time. Control of the PAS can easily be transferred from one MCU to another at f he press of a button.

When the Priority Alarm System is active it can be in a fully operational mode called Alarm System Full On in which the active MCU continually polls remote systems in all coaches and cob cars in the train that are equipped with PAS for their alarm status and monitors all MCU's for any detected faults, and then reports the information to the engineer. The Alarm System Full On mode is the one which should be in use during normal passenger service.

Also when active, the Priority Alarm System can be in an Alarm System On Standby mode which disables alarm monitoring and allows maintenance crews to perform their duties in the train without causing conditions that will generate alarms. An example of this would be the cleaning of Passenger Assist Tape Switches in the cars.

In the Alarm System Shut Down mode the PAS, though powered, is not active. This mode is used during yard operations when the makeup of the train is being changed by the addition and/or removal of cars or the changing of the locomotive. In the Shut Down mode, all MCU systems in the train are non-active. While alarm conditions may exist in the coaches they will be undetected by any MCU, and resetting of the Remote Alarm Unit will not be necessary.

When the System is activated from a Shut Down mode by the engineer, the PAS identifies by road number, the locomotive and cars in the train that are equipped with the System. A self-test routine will be initiated that will check that all RAU's are responding correctly with no alarms and that all other MCU's in the train are answering correctly with no system faults.

System Components
Systems installed in locomotives and cab control cars will normally include these components as shown in Figure 2. Master Control Unit (MCU), Display Head, Data (Event) Recorder, Train Monitoring System (TMS) Audible Alarm.

Figure 2

Systems installed in passenger coaches and cab control cars will normally include these components as shown in Figure 3: Remote Alarm Unit (RAU), Priority Alarm Control Panel, Passenger Assist Tape Switches, Heat Detector, Smoke Detectors, Sonalert Audible Alarms.

Figure 3

The Bach-Simpson Priority Alarm System is extremely flexible and expandable. By adding more sensor inputs and control signal outputs, the PAS can become a highly sophisticated health monitoring system for locomotives and transit rail cars.

At Bach-Simpson, we offer state-of-the-art products combined with dependable customer service and customized engineering support.

Remember, when you buy Bach-Simpson, you buy experience, quality and dependability.

Specifications subject to change without notice, contact Bach-Simpson for latest information.