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SP 5623

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White Gyro Light Red Gyro Light

It has been said that the Southern Pacific designed a light package and then found a locomotive to fit it. They were not terribly consistent though as evidenced by the difference between the first 4 passenger geeps (5600-5603) and the last 4 (5621-5625). Even the freight geeps wore differences, depending on purchase dates. 5621 -5625 also sported number board access doors on both ends, unlike the 5600-5603.

The light package on S.P.'s first order of passenger geeps copied that found on the existing fleet of SD7's. Another interesting feature of these 4 was the lack of access doors for the number boards, an oversight that train crews hated. While not too bad a job on the back end, changing numbers on the front end required opening the steam generator front door on the fireman's side. The engineer's side called for going in the generator compartment , crawling over the toilet and trying to stay out of the way of a lot of hot piping.
5603 Lights

Another variation on the theme is the front end of GP9 5894, an ex-Texas and New Orleans unit, originally numbered 280. Almost identical to the 5603 pictured above, it is also without the number board access doors. But, in this case, the T&NO specified different number boards which are accessable from the outside of the unit. They are a sliding holder which contains the front glass and 5 slots for the number stencils. These transplants from Texas were unique on the S.P.
5894 Gyro Light

Even these two freight geeps wear slightly different light packages. The 5627 has the more common Gyrolight red light while the 5772 is equipped with a red light by Mars. Oscillating lights are often called "Mars Lights" regardless of who made them, just like photo copy machines are usually called "Xerox". Note that the 5772 has an unusual headlight housing and they both have number board access doors.
5627 5772 Gyro Lights

In answer to many questions, there follows a brief explanation of the Gyro light operation.

In the cab, there are 4 switches that affect the lights. First, there is the "Signal Light" breaker which turns the entire system on or off. It is 6th from the right in the first photo. Next, there is a 2 position switch which selects the lights at either "Front" or "Rear" of the locomotive. It is located behind the engineer, within reach on the rear cab wall. Next, there is a control box at the engineers station with 2 switches. One is rotary with 4 positions which are marked "Off", "Red", "Dim" and "Bright". Dim and Bright refer to the white lights only. Lastly, there is a toggle switch (on the side of the box) marked "Run", "Off" and "Inch" which controls the motor in the selected white Gyro light. Either of the white Gyros can therefore be used as an auxiliary headlight by positioning the motor so the light pattern is vertical and turning the motor off. There are 2 ways to turn on the red light. With no pressure (or less than 40 pounds) in the train line and the "Signal Light" breaker turned on, the red light will be running on both ends. When the train line pumps up to more than 40 pounds, the red light will go out and if the rotary selector switch is in either "Dim" or "Bright", the white Gyro light will illuminate on one end. It is possible to turn on the red light on one end only by using the "Red" position of the rotary switch but it will always oscillate. If the train brakes go into emergency, the train line pressure goes to zero. The 40 pound switch turns off which ever white light was on and turns on both red lights. The red warning light in the left photo will be on when either red oscillating light is on. The yellow light indicates that the sanders are operating.

Signal light breaker Signal light direction switch. Signal light control switches

This is the engineer's side cab light.There is an identical one located above the seats on the other side of the cab. The right photo is of the walkway light on the front end. It is there as a safety measure for the crew and there is one at each end of the locomotive.

The left photo is of a "ground light". There are 2 of them, one above the truck, on each side of the cab. The story goes that they are there because it is not possible to tell when a diesel locomotive is moving without seeing the ground. Steamers made noise with each revolution of the wheels, diesels don't. The other photo is of a typical engine room light, this particular one located above the compressor.

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