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NW-603-INT HVAC Control
Replacement for older passenger car HVAC controls
Phone: (503) 231-4808 Fax: (503) 230-0572 E-mail
See where our equipment is located on a typical railway passenger car
When passenger railroads started converting to head-end power, a series of passenger car HVAC controls were developed to work with the heaing, venting and air conditioning systems then being put on the passenger cars. These are typically referred to as "Ogontz boxes" as this was one of the larger manufacturers of these systems. Today, in many cases the HVAC systems are still operable, but the control systems leave a lot to be desired when operated today.
Most of these systems depended on seven or more thermostats in order to determine how the HVAC system should respond to the temperature inside the car. These are usually unreliable after 30 to 40 years of service. The systems typically used fixed set point thermostats so that adjusting the temperature was impossible, and a failure of any of the thermostats could cause system troubles. After nearly 40 years of service, there are various other problems with these systems.
Therefore, due to customer demand for a replacement "Ogontz Box" control system (which was actually built by several manufacturers over the years), Northwest Rail Electric developed the NW-603-INT system. As the original systems consisted of a set of standardized connectors, our system offers easy and quick replacement by conecting to the same primary connector.
The primary system connector (left) is the same as that on the existing equipment. Sensor and HVAC Control connectors (right) connect to Northwest Rail Electric provided sensors and HVAC controls.
The Northwest Rail Electric version of the system consists of two major components:
The Interface Box
The interface box (above right) is slightly smaller than the original control box. This allows it to be installed in the same location as the original box. The box is equipped with the same multiple-pin connector as the original box, allowing it to simply plug into the existing system using the existing primary system connector.
The Temperature Control Strip
Available as either programmable screen (top) or industrial temperature control (bottom):
The temperature control strip is equipped with two stages of heat control, two stages of air conditioning control, and dehumidification, plus temperature display. There is a control voltage circuit breaker, emergency cooling switch, and a HVAC on-off switch. The control strip may be mounted anywhere desired, and does not have to be immediately next to the interface box. This allows the control and display to be on the electrical locker door or other more convenient location than inside the electrical locker itself. The panel is designed to mount in a 19 inch rack, but brackets are available to mount it to a number of different electrical locker situations.
While there is no equivalent to this device in the system it replaces, this piece of the system adds a number of desirable features as well as allowing the system to be controlled by easy to access settings rather than permanetly set thermostats, as it was in the original system.
An additional component is the temperature and humidity sensor, which may be located anywhere desired. Suggested locations include inside the return air duct or in a central location in the car, as both locations give a good indication of the overall temperature of the car. The sensors do not need to be located near the control system, and do not need to be accessed unless they fail.
These systems have proven to be a popular product with those having to deal with the systems they replace.
- System start-up timer. This is a customer-adjustable timer that causes a delay between when the power to the car is first turned on and the HVAC system first starting up. This prevents overloading of the generator if there are a number of cars with the HVAC systems turned on when the HEP power comes on.
- Heat Staging Timers. These provide additional load delay as the system is first turned on.
- Indicators on the cover of the interface box that indicate both the state of the Temperature Control and what signals are being received at the box, as well as the state of the contactors on the HVAC unit itself. This allows for easier system troubleshooting.
- Functions of the original system, including the damper.
- Emergency Cooling switch provides air conditioning even if part of the HVAC control system isn't working correctly.
- Virtually all of the components are common and fairly easy to find in many industrial supply stores.
- The interface box enclosure is equipped with quick release latches to allow for easy access and adjustment of the timers.
- the NW-603-CTL temperature control is easily adjustable to any desired temperature and humidity level.
For More Extensive Passenger Car Rebuilds and System Upgrades:
For those needing more extensive equipment upgrades on their passenger cars, these items may be of interest:
- Air Conditioning Condenser Package for situations where the air conditioning condenser under the car is in poor condition and needs to be completely replaced.
- Air Conditioning Compact Evaporator Package for situations where the air conditioning evaporator, duct blowers, and overhead heat system needs to be replaced. If you are upgrading a car with direct current blowers and steam heat coils, this is your best route, as it puts everything requiring replacement in a single package.
- Solid Element Heaters for situations where only the heater coils need to be replaced.
- Electrical Locker Packages from Northwest Rail Electric may be produced to meet a number of different demands, but our standard packages meet the need of most cars.
- A Direct Current Control System if the requirements of the car include a number of DC loads.
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