Modifying the F3 Headlights

LSC Magazine Article by Brandy Bruce-Sharp

Disassembly of the F3A There are nine screws that hold the F3 shell to the frame. Four of these screws are easily accessed with a standard, small, Phillips head screwdriver. Four more screws are hidden by the fuel tank, which is held in place by two small screws. The ninth screw requires the removal of one truck side-frame in order to get enough swing to access the forward most screw in the nose. The side frame is held in place with three small screws as shown in the photograph.

Once loose, the shell can be removed by pulling the pilot away while gently spreading the shell around the front trucks. Working towards the rear of the F3 gently pull the frame away from the shell as you spread the shell. Two wire harnesses connect the forward lighting board and the smoke units to the chassis main circuit board, detach the wire harnesses by pulling the connectors off the board. The cab interior slides out of the shell easily.

Preparing the Hubblelite Modules I removed the bulb, spring and contacts from the reflector of both of the Hubbell lamp modules. This requires cutting the small wires that connect to the bulb. A pressed in rivet is the center contact for the Hubbell flashlight and it can be a little tough to pry out. The bulb slides out the front of the module. For the lower headlight, I enlarged the hole though the back of the plastic reflector to a .125" diameter so that the original bulb could be used. The upper headlight has a larger diameter bulb so I used my drill press to enlarge the hole through the new reflector using 1/8, 5/32, 3/16 and finally 13/64 drills in my drill press. You must drill all of the way through and into the reflector so use caution and only drill from the back of the module so you do not damage the reflective coating.

Installation of the lower Headlight Start by removing the original bulb and rear (silver) cap that holds it in. I found that I could remove the original headlight lens by breaking the glue bond by squeezing the headlight lens with a pair of small pliers. The lens can then be pushed out of the door leaving a hole for the new reflector. The outside diameter of the Hubbell module is a perfect press fit into the original hole in the door after removing the original bulb and lens assembly. I painted the step in the bezel silver after pressing in the reflector and used hot melt glue to hold the bulb in place from the back. The reflector does not require glue, trust me, in fact you may need to clean a little paint out of the hole to get the reflector to fit.

Installation of the Upper Headlight The upper light was a little more work but was easy to modify. First remove the forward lighting circuit board if you haven’t done this yet. On my F3, the lens assembly was glued in a little better than the lower headlight. I removed the bulb by pulling the silver plastic cap out of the lens piece then put a plastic block between the three mounting posts (the lighting board and body mount posts) and lens insert. I grabbed my largest screwdriver, twisted the screwdriver gently and the lens moved forward until it slid out the front of the body. The upper headlight assembly has a larger ‘lens’ but the mounting hole is actually smaller in diameter than the lower headlight. I enlarged the mounting hole by drilling the inside diameter to 15/32". I started with a 27/64 drill and bored out the mount hole by turning the drill bit by hand with a leather glove. I kept enlarging the hole with subsequently larger drill bits, 7/16, 29/64, and finally 15/32. It was important to me to NOT use a power drill because the chance for damage was too great. I tend to mess up when I get impatient and I wanted as much control as I could get for this particular modification. The new reflector was pressed into the enlarged hole from the inside of the shell. Again, I touched up the edges of the reflector with silver paint and painted the bezel step silver as well to give the appearance of a full diameter reflector. I then glued in the bulb (with hot melt glue) so that it was even with the front edge of the reflector. It is necessary to place the bulb this far forward so that the element is inside the reflector.

Reassembly I had to re-solder the lamp connections to the circuit board, on both bulbs, prior to re-assembly because the leads broke off while handling the bulbs during fitting and gluing. I made new ‘lenses’ from .020 thick, clear, sheet stock that I had on hand. I used the headlight inserts as a guide to scribe the clear plastic with a x-acto knife and bent the plastic so the new lenses popped out. The upper lens fit perfectly and friction fit tight enough to hold itself in place without glue. The lower headlight lens was a tiny bit undersize so I used white glue on the bezel step to hold it in place. I used white glue because it dries clear, doesn’t damage the paint or plastic and can be removed easily if necessary. I knocked out one of the portholes while working on the shell which indicated that they might all need reinforcing. I used hold melt glue to reinforce the original glue on these windows. All that remains is to replace the cab interior and connect the two wire harnesses to the main circuit board. I recommend that you check all of the wiring for damage and test the lights before closing up the engine. I have a power pack with alligator clips I attach to the sliders (finally found a use for those sliders), turn off the motor switch and power up the engine. It is easier to fix any unseen problems as this stage. Finally, reinstall the shell to the chassis and reattach the forward truck side frame. Conclusion The results are quite an improvement over the original headlight assemblies and the materials were priced right at $5.00. If you have the courage to do this modification you will be amazed at how easy it really is, and how much better it makes the model look. Be aware though, I am sure that anything you damage on your model, during this modification, will, most likely, not be covered by the manufacturer's warranty, so be careful and take your time. I am also preparing an article on upgrading other large-scale diesel headlights. The next installment will include the Aristo RS-3, Lil’ Critter, FA-1 and U25-B and the USA Trains GP-7/9 and GP-38 using super bright white LED’s from Ram Track. These upgrades are even easier that the F3A and make dramatic improvements to these large-scale engines as well. Bonus! In the course of writing this article, all of the photos of the interior of the F3 were post modification. What I mean is, I completed the work as a Saturday project a few weeks before I actually wrote the preceding text. I submitted an outline to see if there was any interest in it as an article and mentioned that I had not taken photos. I was asked to open the F3 and take a couple pictures of the finished installation. After opening up the engine, I decided to get some ‘in progress’ pictures. While attempting to remove the upper reflector, my pliers slipped and cracked the smaller diameter portion of the reflector, so I nixed the removal and left it alone. When I reassembled the engine, I assumed that everything was as it was before (disassembly), wrong! I put the engine on my test track and the upper headlight did not work, sigh. I opened up the engine again, assuming I had broken a wire, wrong again! I diagnosed the lighting circuit and tracked the problem down to a broken bulb. That crack I heard was really a crunch. To determine a suitable replacement for the stock bulb I found that the original bulbs are being fed 2volts from a voltage regulator, hmmm? Not having a 3volt bulb, I remembered the HubblelLite is a flashlight, duh! I had purchased two spare HubblelLite modules to take pictures of for the article. I had disassembled one for the article but still had one intact. I soldered the leads from the original bulb to the module and whadya know, it worked, and wow, is it bright!

The bulbs in these modules are xenon, which produces a very bright light at 2volts. Well you know I HAD to do the lower light with an intact module too so I went to buy another one at Home Depot. Of course they were sold out, some bonehead must be buying a lot of them for some reason, so I bought one of the fashlights. These are actually pretty cool kits, they come with the flashlight, batteries installed, a 90° bent light pipe that attaches to the front of the flashlight, a spare bulb and reflector module, a red lens, a spare o-ring and a split ring for your key chain. Since I only needed one module, I still have a working flashlight and the light pipe is excellent for illuminating those (deep) mounting holes in engines. I can get an unobstructed view, down inside, to see if the screw is one that remained inside or is the one that fell out, bounced off the foam work pad, ricochet off of the power pack hit me in the foot, and them rolled under the desk, pretty cool! So if you can’t find the modules by themselves, you can buy one of the flashlight kits and have all you need. I have written to Hubbell for availability but have not heard back. The customer service department is located in Torrance, California, so I would suspect that they are widely available. Update: Larry Cooper has located these replacement light modules at Micro-Mark ( for $5.95 they are Part # 82422

Brandy Bruce-Sharp

My Bio Born in Venice Beach, California, in 1953, I grew up in the Los Angeles area and lived there until 1985 when I moved to Arizona, with my employer at the time. I am currently employed as a systems manager, artist and model builder for a small company that manufactures ammunition loading equipment and improved miniguns and feeder/delinkers for the US Navy. The owner (my boss) indulges his photography and video interests by providing live fire and pyrotechnic effects for video, film and still photographers. I was hired, originally, for my model building, pyrotechnics, explosives, and high power rocketry background. I have worked on several projects that range from the utter destruction of a ’85 Corvette from a helicopter gunship (with dual miniguns) to providing the rocket effects to Peter Chesney for Disney’s ‘Inspector Gadget’.

My model railroad interest started in the late 1950s, with HO. I switched to ‘N’ gauge in the 1960s when ‘N’ was new with an Arnold Rapido freight set. I also got into model rocketry in the mid ‘60s and the battle between rockets and railroads has raged for over 30 years. In 1986 my wife and I bought our current home where I built a new ‘N’ gauge layout and a HOn3 layout in a spare bedroom. In rocketry I participated in projects that flew to 80,000+ feet. In 1998 I launched a 16lb bowling ball to 25,000 feet, at mach 1.75, not bad for an amateur. An accident with rocket fuel in 1995 nearly killed me (~46% full thickness burns, 6 weeks unconscious, three months in a hospital bed).

I had always been aware of LGB and my eyebrow raised with each Aristo-Craft ad I saw in Model Railroader Magazine. Finally, in 1998, looking for a less deadly hobby, I saw an Aristo RS-3 face-to-face and became obsessed. Now I knew why I bought a house with an 80’ x 100’ back yard! I found LSOL in late ’98 and have visited the site almost daily since. I learn something new every week and try to pass on what I have learned to others who seek advice. I consider LSOL an informal club and part of an extended family, unique to Large Scale Model Railroading.

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