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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, 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.

Connectors on the NW-603-INT
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

Photo of the NW-603-CTL
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.

System Features:

These systems have proven to be a popular product with those having to deal with the systems they replace.


A More Extensive Passenger Car Control System

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:


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