Flickering Interior Car Lighting

Flickering Interior Car Lighting

By Roger Heid


So you finally managed to install interior lights into a few passenger cars. Great!  Now you put the whole thing to a test, but, much to your dismay, the lights in some or all cars are flickering, off and on. Disgusting, isn’t it? Before you throw something against a wall or commit similar acts of desperation, let us take a closer look and see what can be done to remedy this situation.

Basically, there are two types of internally lit cars. One type has the lights installed by the manufacturer; the other type requires the installation of an optional lighting kit. Both kinds are equally subject to the flickering lights syndrome.

Now let us try to determine what causes the flickering. Obviously, these interior lights and/or marker lights are not hard wired to the power source. The electrical power is provided by the tracks. In the chain of events, the wheels riding on the tracks are the first point of contact. If the wheels and/or the tracks are dirty, the connection is not consistent; this will result in flickering. In the case of a digital layout, it will also cause the locomotive to display strange behavior.

The next point of contact consists of some kind of springy metal strip that rubs on a metal portion of the wheel set. It may also be installed in the wheel bearing housing of a given piece of rolling stock. The spikes on each axle end will rub against this type of pick up. Either type of pick up is then hard wired to the light assembly. In case of 3-rail AC, a highly visible pickup shoe gets one polarity from the center rail/studs. Again, corrosion and dirt will lead to the flickering.

On some light assemblies, the bulbs are of the screw-in type; they could also be held in place by some spring loaded mechanism. Whatever the lights consist of, the contact points obviously need to be tight and clean, unless they are hardwired.

There are some variations in the physical configuration of these pickup assemblies, as each manufacturer uses its own design. A DIY (do it yourself) modeler can also choose from a variety of aftermarket items.

Now you have a much better understanding of the nature of the beast. Don’t you worry, don’t you fret, here comes the fix.

The easiest remedy is to just run the train until the flickering subsides. The amount of time it takes will vary; in most cases, this will do the trick. The hardcore cases will require your intervention.

For a starter, you need to analyze the mechanics at hand. See that you can find the spots where the pickups get the power from the wheel sets. In some cases, these pickup points are in plain sight; in other cases it takes a little detective work, possibly even a magnifying lens. Needless to say, pickups mounted in the bearing housing pockets are not easily seen, if at all.

There is one good way to clean the contact points, so I found. In previous blogs I had mentioned a substance called ‘White Spirits’, available in hardware stores. Using a small funnel, I transferred an amount of the white spirits into an empty oiler.

I carefully put a small drop on the contact point. Just don’t spill it all over the place. This fluid is also used as paint thinner. It may do a number on something you may have painted. If you don’t have an empty oiler or a similar device handy, you can use a toothpick or such to put a small drop on the contact point.

This method has never failed me, except once. A poor solder connection needed to be re-soldered.

Now there are some special cases. For instance, I have a fully lit passenger train consisting of seven cars (Maerklin). Only one car has a pickup shoe; the rest of the cars are interconnected via current conducting couplers which I installed. Some of the cars had flickering lights. A treatment of the couplers as described above provided an instant cure.

In very rare cases, a given passenger train has no pickup shoe at all. The needed power is drawn from a dedicated locomotive via its own current conducting coupler. If the lights flicker, use the same fix as described in the previous paragraph.

In all cases described so far, the wheels will always provide one of the two polarities.

I will refrain from mentioning some rather exotic cases in which flickering is nary a problem.

If you have any further questions, please post them in the Forum under the appropriate topic. Thank you.

Happy Railroading!






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